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Question 2621Question

A right triangle has legs of length x0.5x - 0.5 inches and 2x2x inches, and a hypotenuse of length 2x+0.52x + 0.5 inches. What is the value of xx?

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Answer: 3

Answer

3
Applying the Pythagorean theorem to the right triangle yields (x0.5)2+(2x)2=(2x+0.5)2(x - 0.5)^2 + (2x)^2 = (2x + 0.5)^2. Expanding the terms gives x2x+0.25+4x2=4x2+2x+0.25x^2 - x + 0.25 + 4x^2 = 4x^2 + 2x + 0.25. Subtracting 4x24x^2 and 0.250.25 from both sides simplifies the equation to x2x=2xx^2 - x = 2x. Subtracting 2x2x from both sides gives the standard quadratic equation x23x=0x^2 - 3x = 0. Factoring this expression gives x(x3)=0x(x - 3) = 0, which yields solutions x=0x = 0 and x=3x = 3. Since the side length x0.5x - 0.5 must be positive, xx must be greater than 0.50.5. Therefore, the only valid solution is 33.

Step-by-Step Solution

1
Set up the equation using the Pythagorean theorem, a2+b2=c2a^2 + b^2 = c^2, with the given side lengths.
(x0.5)2+(2x)2=(2x+0.5)2(x - 0.5)^2 + (2x)^2 = (2x + 0.5)^2
The Pythagorean theorem relates the legs and hypotenuse of any right triangle.
2
Expand each squared term algebraically.
(x2x+0.25)+4x2=4x2+2x+0.25(x^2 - x + 0.25) + 4x^2 = 4x^2 + 2x + 0.25
Expanding the binomials allows us to combine like terms and simplify the equation.
3
Subtract 4x24x^2 and 0.250.25 from both sides of the equation.
x2x=2xx^2 - x = 2x
Simplifying the equation makes it easier to solve.
4
Move all terms to the left side to write the quadratic equation in standard form.
x23x=0x^2 - 3x = 0
A quadratic equation must be set to zero to be solved by factoring.
5
Factor the quadratic expression.
x(x3)=0x(x - 3) = 0
Factoring allows us to find the roots of the equation.
6
Solve for xx and choose the value that makes all side lengths positive.
x=3x = 3 (since x=0x = 0 is not a valid length because a side length x0.5x - 0.5 must be greater than 00)
Only a positive value of xx greater than 0.50.5 yields physically possible side lengths for the triangle.

Key Concept

Setting up and solving quadratic equations using algebraic expansion and the Pythagorean theorem
Estimated Time:1m 30s
Question 2622Question

In the standard (x,y)(x, y) coordinate plane, a line segment has endpoints at P(2,1)P(2, 1) and Q(8,5)Q(8, 5). Line LL is parallel to segment PQPQ and passes through the point (3,2)(3, -2). If the point (9,y)(9, y) also lies on line LL, what is the value of yy?

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Answer: 2

Answer

The value of yy is 22.
The slope of segment PQPQ is 5182=23\frac{5 - 1}{8 - 2} = \frac{2}{3}. Since line LL is parallel to segment PQPQ, its slope is also 23\frac{2}{3}. The slope of line LL through (3,2)(3, -2) and (9,y)(9, y) is given by y(2)93=y+26\frac{y - (-2)}{9 - 3} = \frac{y + 2}{6}. Equating the two slopes yields y+26=23\frac{y + 2}{6} = \frac{2}{3}, which simplifies to y+2=4y + 2 = 4, so y=2y = 2.

Step-by-Step Solution

1
Calculate the slope of segment PQPQ.
Slope of PQ=23PQ = \frac{2}{3}
Since parallel lines have equal slopes, finding the slope of the reference segment PQPQ is the first step in determining the slope of line LL.
2
Set up the slope equation for line LL using its parallel relationship to segment PQPQ.
y(2)93=23\frac{y - (-2)}{9 - 3} = \frac{2}{3}
Because line LL is parallel to segment PQPQ, its slope must also be 23\frac{2}{3}. The slope of line LL is calculated using the points (3,2)(3, -2) and (9,y)(9, y).
3
Solve the equation for yy.
y=2y = 2
Simplifying the numerator gives y+2y + 2 and the denominator gives 66. Multiplying both sides of y+26=23\frac{y + 2}{6} = \frac{2}{3} by 66 yields y+2=4y + 2 = 4, which solves to y=2y = 2.

Key Concept

Parallel lines have equal slopes in the coordinate plane.
Question 2623Question

Given that cosθ=45\cos\theta = \frac{4}{5} and the terminal side of angle θ\theta lies in Quadrant IV, what is the value of tanθ\tan\theta?

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Answer: 34-\frac{3}{4}

Answer

34-\frac{3}{4}
The correct answer is 34-\frac{3}{4}. Since the angle θ\theta has its terminal side in Quadrant IV, its cosine is positive and its sine is negative. Using the Pythagorean identity sin2θ+cos2θ=1\sin^2\theta + \cos^2\theta = 1, we find sin2θ+(45)2=1\sin^2\theta + \left(\frac{4}{5}\right)^2 = 1, which simplifies to sin2θ=925\sin^2\theta = \frac{9}{25}. Because sine is negative in Quadrant IV, sinθ=35\sin\theta = -\frac{3}{5}. Finally, applying the quotient identity tanθ=sinθcosθ\tan\theta = \frac{\sin\theta}{\cos\theta}, we get tanθ=3/54/5=34\tan\theta = \frac{-3/5}{4/5} = -\frac{3}{4}.

Step-by-Step Solution

1
Determine the sign of sinθ\sin\theta in Quadrant IV.
sinθ<0\sin\theta < 0
In Quadrant IV, the x-coordinates (representing cosine) are positive, and the y-coordinates (representing sine) are negative.
2
Use the Pythagorean identity sin2θ+cos2θ=1\sin^2\theta + \cos^2\theta = 1 to calculate the value of sinθ\sin\theta.
sinθ=35\sin\theta = -\frac{3}{5}
Substituting cosθ=45\cos\theta = \frac{4}{5} gives sin2θ+(45)2=1    sin2θ=11625=925\sin^2\theta + \left(\frac{4}{5}\right)^2 = 1 \implies \sin^2\theta = 1 - \frac{16}{25} = \frac{9}{25}. Taking the negative square root because sine is negative in Quadrant IV yields 35-\frac{3}{5}.
3
Use the quotient identity tanθ=sinθcosθ\tan\theta = \frac{\sin\theta}{\cos\theta} to calculate tanθ\tan\theta.
tanθ=34\tan\theta = -\frac{3}{4}
Dividing the value of sinθ\sin\theta by cosθ\cos\theta yields 3/54/5=34\frac{-3/5}{4/5} = -\frac{3}{4}.

Key Concept

Fundamental Trigonometric Identities
Question 2624Question

A dog is tied to a post in the center of a flat, grassy yard with a leash that is 12 feet12\text{ feet} long. If the dog walks along an arc formed by a central angle of π3\frac{\pi}{3} radians, what is the length, in feet, of the path the dog travels?

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Answer: 4π4\pi

Answer

The correct option is the one stating 4π4\pi.
The length of the path traveled by the dog is the arc length of a circle with a radius of 1212 feet and a central angle of π3\frac{\pi}{3} radians. Using the radian arc length formula, s=rθs = r\theta, substituting r=12r = 12 and θ=π3\theta = \frac{\pi}{3} yields s=12×π3=4πs = 12 \times \frac{\pi}{3} = 4\pi feet.

Step-by-Step Solution

1
Identify the given values from the problem statement.
The radius of the circular path is r=12r = 12 feet, and the central angle is θ=π3\theta = \frac{\pi}{3} radians.
These parameters are required to calculate the arc length of the path.
2
Recall the formula for the arc length of a circle when the angle is in radians.
The formula is s=rθs = r\theta.
Since the angle is given in radians, the arc length is directly the product of the radius and the angle.
3
Substitute the values into the formula and calculate the result.
s=12×π3=4πs = 12 \times \frac{\pi}{3} = 4\pi.
Multiplying the radius by the angle in radians gives the length of the path traveled.

Key Concept

Calculating the arc length of a circle when the central angle is measured in radians using the formula s=rθs = r\theta.
Question 2625Question

In the standard (x,y)(x, y) coordinate plane, quadrilateral ABCDABCD is a kite that is not a rhombus, with AB=BCAB = BC and AD=CDAD = CD. The vertices AA and CC are located at (2,5)(2, 5) and (8,13)(8, 13), respectively. If the vertex BB is located at (9,6)(9, 6), which of the following could be the coordinates of vertex DD?

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Answer: (3,15)(-3, 15)

Answer

The coordinates (3,15)(-3, 15)
The correct answer is the coordinates (3,15)(-3, 15). The diagonals of a kite are perpendicular, and the diagonal BDBD perpendicularly bisects the diagonal ACAC. The midpoint of ACAC is M(5,9)M(5, 9) and the slope of ACAC is 43\frac{4}{3}. Therefore, the line containing diagonal BDBD must pass through M(5,9)M(5, 9) with a perpendicular slope of 34-\frac{3}{4}. The equation of this line is 3x+4y=513x + 4y = 51. Testing the coordinates (3,15)(-3, 15) shows that the point lies on this line. Since the distance from (3,15)(-3, 15) to M(5,9)M(5, 9) is 1010 units while the distance from B(9,6)B(9, 6) to M(5,9)M(5, 9) is 55 units, the diagonals do not bisect each other, confirming the kite is not a rhombus.

Step-by-Step Solution

1
Find the midpoint MM of diagonal ACAC.
M=(2+82,5+132)=(5,9)M = \left(\frac{2 + 8}{2}, \frac{5 + 13}{2}\right) = (5, 9)
In a kite where AB=BCAB = BC and AD=CDAD = CD, the diagonal BDBD perpendicularly bisects the diagonal ACAC. Therefore, the line containing BDBD must pass through the midpoint of ACAC.
2
Calculate the slope of diagonal ACAC.
mAC=13582=86=43m_{AC} = \frac{13 - 5}{8 - 2} = \frac{8}{6} = \frac{4}{3}
The slope is needed to find the perpendicular slope of the line containing diagonal BDBD.
3
Determine the slope of the line containing diagonal BDBD.
mBD=1mAC=34m_{BD} = -\frac{1}{m_{AC}} = -\frac{3}{4}
Since the diagonals of a kite are perpendicular, the slope of the line containing diagonal BDBD is the negative reciprocal of the slope of diagonal ACAC.
4
Write the equation of the line containing diagonal BDBD and test the coordinates of vertex DD.
y9=34(x5)3x+4y=51y - 9 = -\frac{3}{4}(x - 5) \Rightarrow 3x + 4y = 51
Using the point-slope formula with the midpoint M(5,9)M(5, 9) and slope 34-\frac{3}{4} gives the line equation. Testing the correct option (3,15)(-3, 15) gives 3(3)+4(15)=9+60=513(-3) + 4(15) = -9 + 60 = 51, which lies on this line. Furthermore, the distance from (3,15)(-3, 15) to M(5,9)M(5, 9) is (35)2+(159)2=10\sqrt{(-3-5)^2 + (15-9)^2} = 10, which is different from the distance of 55 between (9,6)(9, 6) and M(5,9)M(5, 9), ensuring the kite is not a rhombus.

Key Concept

Diagonals of a kite are perpendicular, and the diagonal connecting the vertices between the unequal adjacent sides perpendicularly bisects the other diagonal.
Question 2626Question

For each angle or terminal ray described on the left, match it to the correct coordinates (x,y)(x, y) of its intersection with the unit circle in the standard coordinate plane on the right.

Click a left item, then click its matching right item

Items

The angle θ1\theta_1 in standard position obtained by starting at the positive xx-axis, rotating counterclockwise by 13π3\frac{13\pi}{3} radians, and then rotating clockwise by 570570^\circ.
The angle θ2\theta_2 in standard position whose terminal ray passes through the point of intersection on the unit circle after a point starts at (0,1)(0, -1) and rotates counterclockwise by 23π4\frac{23\pi}{4} radians.
The angle θ3\theta_3 in standard position that is coterminal with the angle ϕ=1020\phi = -1020^\circ.
The angle θ4\theta_4 in standard position whose terminal ray is symmetric with respect to the yy-axis to the terminal ray of the angle 4π3\frac{4\pi}{3} radians.

Matches

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Answer

The correct matches associate the angle of 7pi/6 radians with coordinates (-sqrt(3)/2, -1/2); the angle of 5pi/4 radians with coordinates (-sqrt(2)/2, -sqrt(2)/2); the angle of pi/3 radians with coordinates (1/2, sqrt(3)/2); and the y-axis reflected angle of 4pi/3 radians with coordinates (1/2, -sqrt(3)/2).
Each description on the left simplifies to a unique angle in standard position on the unit circle. The coordinates on the right represent the exact (cosθ,sinθ)(\cos\theta, \sin\theta) values for each corresponding angle: the angle of 7π6\frac{7\pi}{6} radians corresponds to coordinates (32,12)\left(-\frac{\sqrt{3}}{2}, -\frac{1}{2}\right); the angle of 5π4\frac{5\pi}{4} radians corresponds to coordinates (22,22)\left(-\frac{\sqrt{2}}{2}, -\frac{\sqrt{2}}{2}\right); the angle of π3\frac{\pi}{3} radians corresponds to coordinates (12,32)\left(\frac{1}{2}, \frac{\sqrt{3}}{2}\right); and the terminal ray symmetric to the terminal ray of 4π3\frac{4\pi}{3} radians across the yy-axis corresponds to coordinates (12,32)\left(\frac{1}{2}, -\frac{\sqrt{3}}{2}\right).

Step-by-Step Solution

1
Analyze the first angle description by converting all angle measures to a common unit (radians) and computing the net rotation.
For the first angle, 570=19π6570^\circ = \frac{19\pi}{6} radians, and the net rotation is 13π319π6=7π6\frac{13\pi}{3} - \frac{19\pi}{6} = \frac{7\pi}{6} radians.
Converting degrees to radians and subtracting the clockwise rotation from the counterclockwise rotation simplifies the angle to a standard radian value.
2
For the second angle, express the starting point as an angle in radians and add the given counterclockwise rotation, then find the coterminal angle in [0,2π)[0, 2\pi).
Starting at (0,1)(0, -1) is equivalent to 3π2\frac{3\pi}{2} radians. Total rotation is 3π2+23π4=29π4\frac{3\pi}{2} + \frac{23\pi}{4} = \frac{29\pi}{4} radians, which is coterminal with 29π46π=5π4\frac{29\pi}{4} - 6\pi = \frac{5\pi}{4} radians.
Using the standard position angle of the starting point allows us to sum the rotations and determine the final terminal ray position.
3
Determine the coterminal angle for 1020-1020^\circ in the interval [0,360)[0, 360^\circ) and convert it to radians.
1020+1080=60-1020^\circ + 1080^\circ = 60^\circ, which equals π3\frac{\pi}{3} radians.
Adding multiples of 360360^\circ finds the equivalent positive angle within one full revolution.
4
Find the coordinates of the terminal ray of 4π3\frac{4\pi}{3} radians on the unit circle, reflect the point across the yy-axis, and determine the coordinates of the resulting point.
The coordinate point of 4π3\frac{4\pi}{3} is (12,32)\left(-\frac{1}{2}, -\frac{\sqrt{3}}{2}\right). Reflecting this point across the yy-axis yields (12,32)\left(\frac{1}{2}, -\frac{\sqrt{3}}{2}\right).
Symmetry across the yy-axis negates the xx-coordinate of the point on the unit circle.
5
Match each of the simplified angles to their corresponding standard coordinates (x,y)=(cosθ,sinθ)(x, y) = (\cos\theta, \sin\theta) on the unit circle.
The angle 7π6\frac{7\pi}{6} matches (32,12)\left(-\frac{\sqrt{3}}{2}, -\frac{1}{2}\right); 5π4\frac{5\pi}{4} matches (22,22)\left(-\frac{\sqrt{2}}{2}, -\frac{\sqrt{2}}{2}\right); π3\frac{\pi}{3} matches (12,32)\left(\frac{1}{2}, \frac{\sqrt{3}}{2}\right); and the reflected terminal ray matches (12,32)\left(\frac{1}{2}, -\frac{\sqrt{3}}{2}\right).
Evaluating the sine and cosine functions at each angle yields the final coordinates.

Key Concept

Identifying terminal coordinates of angles on the unit circle by converting between degrees and radians, calculating coterminal angles, and applying coordinate symmetries.
Estimated Time:3m 0s
Question 2627Question

In the standard (x,y)(x, y) coordinate plane, a right triangle has vertices A(2,3)A(-2, -3), B(6,3)B(6, -3), and C(6,y)C(6, y), where y>0y > 0. If the hypotenuse of the triangle has a length of 17 units, what is the value of yy?

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Answer: 12

Answer

The correct value of yy is 1212.
The horizontal leg ABAB has a length of 6(2)=86 - (-2) = 8 units. By the Pythagorean theorem, the vertical leg BCBC has a length of 17282=15\sqrt{17^2 - 8^2} = 15 units. Since the vertex BB is at (6,3)(6, -3) and CC is at (6,y)(6, y) with y>0y > 0, the vertical distance is y(3)=15y - (-3) = 15, which yields y=12y = 12.

Step-by-Step Solution

1
Determine the length of the horizontal leg ABAB.
The length of ABAB is 88 units.
Since vertices A(2,3)A(-2, -3) and B(6,3)B(6, -3) share the same yy-coordinate, the segment is horizontal. The length is the positive difference between their xx-coordinates: 6(2)=86 - (-2) = 8.
2
Use the Pythagorean theorem to calculate the length of the vertical leg BCBC.
The length of BCBC is 1515 units.
Since ABAB is horizontal and BCBC is vertical (vertices BB and CC share the same xx-coordinate of 66), the angle at BB is a right angle. The hypotenuse is AC=17AC = 17. By the Pythagorean theorem, AB2+BC2=AC2    82+BC2=172    64+BC2=289    BC2=225    BC=15AB^2 + BC^2 = AC^2 \implies 8^2 + BC^2 = 17^2 \implies 64 + BC^2 = 289 \implies BC^2 = 225 \implies BC = 15.
3
Set up an equation using the coordinates to find yy.
y=12y = 12
The length of the vertical segment BCBC is the difference in yy-coordinates: y(3)=15|y - (-3)| = 15, which simplifies to y+3=15y + 3 = 15 since y>0y > 0. Solving for yy yields y=12y = 12.

Key Concept

Using coordinate differences and the Pythagorean theorem to determine unknown vertices of geometric figures in the coordinate plane.

Alternative Method

Alternatively, you can apply the distance formula directly between the vertices A(2,3)A(-2, -3) and C(6,y)C(6, y) with a distance of 17 units: (6(2))2+(y(3))2=17    82+(y+3)2=289    (y+3)2=225\sqrt{(6 - (-2))^2 + (y - (-3))^2} = 17 \implies 8^2 + (y + 3)^2 = 289 \implies (y + 3)^2 = 225, which yields y+3=15    y=12y + 3 = 15 \implies y = 12 since y>0y > 0.
Estimated Time:1m 30s
Question 2628Question

A vertical flagpole is secured by two straight guide wires anchored to the flat ground on opposite sides of the pole. The first guide wire is 1313 feet long and its anchor is 55 feet from the base of the pole. The second guide wire is anchored such that it makes a 3030^\circ angle of elevation with the ground. If both guide wires are attached to the flagpole at the same height, what is the length, in feet, of the second guide wire?

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Answer: 24

Answer

The length of the second guide wire is 2424 feet.
The correct answer is 2424. First, the height of the attachment point is found using the Pythagorean theorem: h=13252=12h = \sqrt{13^2 - 5^2} = 12 feet. Since the second wire makes a 3030^\circ angle of elevation with the ground, it forms a 30-60-90 right triangle where the flagpole height of 1212 feet is the leg opposite the 3030^\circ angle. The length of the wire is the hypotenuse of this triangle, which is twice the length of the opposite leg: 2×12=242 \times 12 = 24 feet.

Step-by-Step Solution

1
Use the Pythagorean theorem to calculate the height of the flagpole where the guide wires are attached.
The flagpole height is 1212 feet.
The first guide wire, the flagpole, and the ground form a right triangle with a hypotenuse of 1313 feet and a horizontal leg of 55 feet. Thus, h=13252=16925=12h = \sqrt{13^2 - 5^2} = \sqrt{169 - 25} = 12.
2
Apply the properties of a 30-60-90 special right triangle to find the length of the second guide wire.
The length of the second guide wire is 2424 feet.
The second wire forms a 30-60-90 right triangle with the flagpole and the ground. The angle of elevation is 3030^\circ, which means the side opposite this angle is the vertical height of the flagpole (1212 feet). In a 30-60-90 triangle, the hypotenuse (the wire length) is twice the length of the shorter leg (opposite the 3030^\circ angle), so the length is 2×12=242 \times 12 = 24.

Key Concept

Applying the Pythagorean Theorem and the ratio properties of 30-60-90 special right triangles to solve multi-step geometry problems.
Question 2629Question

A goat is tethered to one of the outer corners of a flat, rectangular shed that measures 6 meters6\text{ meters} by 8 meters8\text{ meters}. The tether is 10 meters10\text{ meters} long. Assuming the goat remains outside the shed, what is the total area, in square meters, of the region the goat can graze?

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Answer: 80π80\pi

Answer

The correct grazing area is 80π80\pi square meters.
The total grazing area is the sum of three sectors: a sector of radius 10 meters10\text{ meters} with central angle 270270^\circ (area 75π75\pi), a sector of radius 4 meters4\text{ meters} with central angle 9090^\circ (area 4π4\pi), and a sector of radius 2 meters2\text{ meters} with central angle 9090^\circ (area π\pi). Adding these yields 80π80\pi square meters.

Step-by-Step Solution

1
Determine the area of the main sector.
The main sector has a radius of 10 meters10\text{ meters} and a central angle of 36090=270360^\circ - 90^\circ = 270^\circ. The area is 270360×π×102=75π\frac{270}{360} \times \pi \times 10^2 = 75\pi square meters.
The corner of the rectangular shed blocks 9090^\circ of a full circle, leaving a 270270^\circ sector.
2
Determine the area of the sector at the corner adjacent to the 66-meter side.
The tether wraps around the corner, leaving a remaining length of 106=4 meters10 - 6 = 4\text{ meters}. It sweeps through an angle of 9090^\circ. The area is 90360×π×42=4π\frac{90}{360} \times \pi \times 4^2 = 4\pi square meters.
When the tether extends past the adjacent corner along the 66-meter side, the pivot point becomes that corner and the tether length decreases by the side length.
3
Determine the area of the sector at the corner adjacent to the 88-meter side.
The tether wraps around the corner, leaving a remaining length of 108=2 meters10 - 8 = 2\text{ meters}. It sweeps through an angle of 9090^\circ. The area is 90360×π×22=π\frac{90}{360} \times \pi \times 2^2 = \pi square meters.
When the tether extends past the adjacent corner along the 88-meter side, the pivot point becomes that corner and the tether length decreases by the side length.
4
Check for overlap and calculate the total grazing area.
The total area is 75π+4π+π=80π75\pi + 4\pi + \pi = 80\pi square meters.
The two smaller sectors are at different corners of the rectangular shed and do not overlap. Summing the three sector areas gives the total grazing region.

Key Concept

Calculating sector areas by determining the correct radii and central angles based on geometric constraints.
Question 2630Question

An angle in standard position measures 468-468^\circ. What is the radian measure of the coterminal angle that lies in the interval [0,2π)[0, 2\pi)?

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Answer: 7π5\frac{7\pi}{5}

Answer

The correct radian measure of the coterminal angle is 7π5\frac{7\pi}{5}.
To find the correct radian measure, first determine the positive coterminal angle in degrees by adding multiples of 360360^\circ until the angle lies in the interval [0,360)[0^\circ, 360^\circ). Adding 720720^\circ to 468-468^\circ results in 252252^\circ. Convert this angle to radians by multiplying by π180\frac{\pi}{180^\circ}, which yields 252π180\frac{252\pi}{180}. Dividing the numerator and denominator by their greatest common divisor, 3636, simplifies the expression to 7π5\frac{7\pi}{5} radians.

Step-by-Step Solution

1
Find a positive coterminal angle in degrees by adding multiples of 360360^\circ to the initial angle.
468+360=108-468^\circ + 360^\circ = -108^\circ, and 108+360=252-108^\circ + 360^\circ = 252^\circ.
Adding 720720^\circ (two full rotations) to 468-468^\circ shifts the angle into the standard positive range [0,360)[0^\circ, 360^\circ) while maintaining the same terminal ray.
2
Convert the coterminal angle from degrees to radians by multiplying by the conversion factor π180\frac{\pi}{180^\circ}.
252×π180=252π180252^\circ \times \frac{\pi}{180^\circ} = \frac{252\pi}{180} radians.
Since π\pi radians corresponds to 180180^\circ, multiplying by π180\frac{\pi}{180^\circ} changes the unit of measure from degrees to radians.
3
Simplify the fraction 252π180\frac{252\pi}{180} by dividing both the numerator and the denominator by their greatest common divisor.
Dividing 252252 and 180180 by their greatest common divisor of 3636 yields 7π5\frac{7\pi}{5} radians.
Simplifying the fraction expresses the final radian measure in its standard, reduced form.

Key Concept

Finding positive coterminal angles and converting degree measures to radian measures on the unit circle.

Alternative Method

Convert the initial angle of 468-468^\circ directly to radians first by multiplying by π180\frac{\pi}{180^\circ}, yielding 13π5-\frac{13\pi}{5} radians. To find the positive coterminal angle in the interval [0,2π)[0, 2\pi), add multiples of 2π2\pi radians (which is 10π5\frac{10\pi}{5}): 13π5+10π5=3π5-\frac{13\pi}{5} + \frac{10\pi}{5} = -\frac{3\pi}{5}, and then 3π5+10π5=7π5-\frac{3\pi}{5} + \frac{10\pi}{5} = \frac{7\pi}{5} radians.
Estimated Time:2m 0s
Question 2631Question

Passage

The Settlement Movement and the Foundations of Hull House

In the late nineteenth century, rapid industrialization and urbanization in the United States led to overcrowded cities and widespread poverty among working-class immigrant populations. In Chicago, Illinois, this reality was particularly acute, as thousands of new arrivals sought work in the city's factories and meatpacking plants. It was against this backdrop of social inequality that Jane Addams, a young woman from a wealthy Illinois family, embarked on a mission to bridge the gap between different social classes.

Addams’s journey toward social reform began in earnest in 1883 during a tour of Europe. During her travels, she witnessed the stark contrast between the lives of the wealthy elite and the urban poor. However, the pivotal moment of her journey occurred in 1887 when she visited Toynbee Hall in London's East End. Toynbee Hall was the world's first university settlement house, a place where wealthy university graduates lived and worked alongside local residents in an effort to alleviate poverty and share cultural resources. Inspired by this model, Addams resolved to establish a similar institution in the United States.

Upon returning to Chicago in 1889, Addams and her close friend Ellen Gates Starr began searching for a suitable location in the city's crowded West Side. They eventually located a large, run-down mansion that had been built in 1856 by a wealthy real estate developer named Charles Hull. The mansion, located at the corner of Halsted and Polk Streets, was surrounded by tenements, factories, and saloons, making it the ideal location for a settlement project. Addams and Starr leased the home, which they named Hull House in honor of its original owner, and moved in to begin their work.

In September 1889, Hull House officially opened its doors to the public. Initially, Addams and Starr focused on addressing the immediate practical needs of the neighborhood's immigrant residents. They established a nursery and a kindergarten to care for the young children of working mothers, and they organized social clubs and reading groups for older children and adults. The response from the community was overwhelming, and the house quickly became a bustling center of neighborhood life.

As the needs of the neighborhood grew, so did the facilities of Hull House. In 1891, the settlement house expanded its physical footprint with the construction of the Butler Art Gallery, which provided local residents with access to art exhibitions and lectures. A few years later, in 1893, Hull House added a public playground, which was the first of its kind in the city of Chicago. By 1895, the complex had grown to include a cooperative residence for young working women, known as the Jane Club, which offered affordable housing and a supportive community.

Through its rapid growth, Hull House demonstrated the effectiveness of the settlement house model. Addams and her colleagues did not merely provide charity; they lived as neighbors to those they served, working together to advocate for child labor laws, housing reform, and sanitation improvements. By the early twentieth century, Hull House had evolved from a single rented mansion into a sprawling thirteen-building complex, serving as a national model for social reform and community empowerment.

Based on the passage, arrange the following events in the chronological order in which they occurred, from the earliest to the latest.

Drag items to arrange them in the correct order

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Answer

The correct chronological order of the events is: Jane Addams visits Toynbee Hall in London's East End, followed by Jane Addams and Ellen Gates Starr leasing the mansion built by Charles Hull, then the construction of the Butler Art Gallery, and finally the addition of a public playground to the Hull House complex.
The correct chronological order of the events is explicitly provided in the passage with specific dates: Jane Addams visited Toynbee Hall in 1887; she and Ellen Gates Starr leased the Charles Hull mansion in 1889; the Butler Art Gallery was constructed in 1891; and the public playground was added in 1893.

Step-by-Step Solution

1
Locate the mention of Jane Addams visiting Toynbee Hall in the text.
The text states she visited Toynbee Hall in 1887.
This establishes the year for the first event.
2
Locate the details about leasing the Charles Hull mansion.
The text states she and Ellen Gates Starr returned to Chicago and leased the mansion in 1889.
This establishes the year for the second event.
3
Locate the details regarding the Butler Art Gallery.
The text explicitly states the gallery was constructed in 1891.
This establishes the year for the third event.
4
Locate the details regarding the public playground.
The text explicitly states the playground was added in 1893.
This establishes the year for the final event.

Key Concept

Identifying Explicit Details
Question 2632Question

A projectile is launched vertically upward from an initial height of 55 meters. Its height, h(t)h(t) in meters, tt seconds after launch is given by the function h(t)=4.9t2+19.6t+5h(t) = -4.9t^2 + 19.6t + 5. To the nearest tenth of a second, how many seconds after launch does the projectile reach a height of 1515 meters on its way down?

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Answer: 3.4

Answer

To the nearest tenth of a second, the projectile reaches a height of 1515 meters on its way down at 3.43.4 seconds.
The correct answer is 3.43.4 seconds. Setting the height equation h(t)=15h(t) = 15 yields 4.9t2+19.6t10=0-4.9t^2 + 19.6t - 10 = 0. Solving this quadratic equation via the quadratic formula gives two solutions: t0.6t \approx 0.6 seconds and t3.4t \approx 3.4 seconds. The projectile travels upward first, passing the 1515-meter mark at 0.60.6 seconds, and then descends, passing the 1515-meter mark again at 3.43.4 seconds.

Step-by-Step Solution

1
Set up the quadratic equation by setting the height function h(t)h(t) equal to 1515.
4.9t2+19.6t+5=15-4.9t^2 + 19.6t + 5 = 15
This allows us to find the specific values of time tt when the height of the projectile is exactly 1515 meters.
2
Rearrange the quadratic equation into the standard form at2+bt+c=0at^2 + bt + c = 0 by subtracting 1515 from both sides.
4.9t2+19.6t10=0-4.9t^2 + 19.6t - 10 = 0
Writing the equation in standard form is necessary before applying the quadratic formula.
3
Substitute the coefficients a=4.9a = -4.9, b=19.6b = 19.6, and c=10c = -10 into the quadratic formula.
t=19.6±(19.6)24(4.9)(10)2(4.9)t = \frac{-19.6 \pm \sqrt{(19.6)^2 - 4(-4.9)(-10)}}{2(-4.9)}
Since the quadratic equation has non-integer decimal coefficients, using the quadratic formula is the most reliable method to solve for the roots.
4
Simplify the discriminant and calculate the two values of tt.
t0.6t \approx 0.6 and t3.4t \approx 3.4
The discriminant is 19.62196=188.1619.6^2 - 196 = 188.16. Taking the square root gives 188.1613.72\sqrt{188.16} \approx 13.72, resulting in two real roots.
5
Determine which root corresponds to the projectile's motion on the way down.
t3.4t \approx 3.4 seconds
The smaller root (0.60.6 seconds) represents the first time the projectile reaches 1515 meters while ascending. The larger root (3.43.4 seconds) represents the time the projectile passes 1515 meters while descending.

Key Concept

Solving quadratic equations with decimal coefficients using the quadratic formula and interpreting the physical context of the roots.
Question 2633Question

A circle has a radius of 12 centimeters12\text{ centimeters}. What is the length, in centimeters, of the arc intercepted by a central angle of 3030^\circ?

Show answer & explanation

Answer: 2π2\pi

Answer

2π2\pi centimeters
To find the arc length, multiply the total circumference of the circle, 2πr2\pi r, by the fraction of the circle represented by the central angle, θ360\frac{\theta}{360^\circ}. With a radius of 1212 centimeters and a central angle of 3030^\circ, this calculation yields 2π(12)×30360=24π×112=2π2\pi (12) \times \frac{30}{360} = 24\pi \times \frac{1}{12} = 2\pi centimeters.

Step-by-Step Solution

1
Identify the formula for arc length: s=2πr(θ360)s = 2\pi r \left(\frac{\theta}{360^\circ}\right), where rr is the radius and θ\theta is the central angle in degrees.
Formula established: s=2πr(θ360)s = 2\pi r \left(\frac{\theta}{360^\circ}\right)
Arc length is the fraction of the total circumference determined by the central angle.
2
Substitute the given radius r=12 cmr = 12\text{ cm} and central angle θ=30\theta = 30^\circ into the formula.
Equation set up: s=2π(12)(30360)s = 2\pi (12) \left(\frac{30}{360}\right)
This sets up the specific calculation for the given circle.
3
Simplify the expression to find the final arc length.
s=24π(112)=2πs = 24\pi \left(\frac{1}{12}\right) = 2\pi
Simplification yields the exact length of the arc in terms of π\pi.

Key Concept

The length of an arc is proportional to the fraction of the circle's circumference represented by the central angle.
Estimated Time:1m 0s
Question 2634Question

In rhombus ABCDABCD, the perimeter is 100100 and the length of diagonal BDBD is 3030. Point PP lies on diagonal ACAC such that the ratio of the length of segment APAP to the length of segment PCPC is 3:73:7. What is the length of segment BPBP?

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Answer: 17

Answer

The length of segment BPBP is 17.
The correct answer is found by utilizing the properties of a rhombus. A rhombus has four congruent sides, meaning each side of a rhombus with perimeter 100100 has a length of 2525. The diagonals of a rhombus are perpendicular bisectors of one another. Letting OO be the intersection of the diagonals, we find BO=15BO = 15 since diagonal BD=30BD = 30. Using the Pythagorean theorem on right triangle AOBAOB, we determine that the other half-diagonal is AO=252152=20AO = \sqrt{25^2 - 15^2} = 20, which means the full diagonal AC=40AC = 40. Point PP divides ACAC in the ratio 3:73:7, meaning AP=12AP = 12 and PC=28PC = 28. The distance from PP to the intersection point OO is OP=AOAP=2012=8OP = AO - AP = 20 - 12 = 8. Finally, applying the Pythagorean theorem to right triangle BOPBOP with legs BO=15BO = 15 and OP=8OP = 8 yields BP=152+82=17BP = \sqrt{15^2 + 8^2} = 17.

Step-by-Step Solution

1
Calculate the side length of rhombus ABCDABCD from its perimeter.
Each side length is 2525.
A rhombus has four equal sides, so the side length is the perimeter divided by four: 1004=25\frac{100}{4} = 25.
2
Find the length of half of diagonal BDBD.
BO=15BO = 15, where OO is the intersection of diagonals ACAC and BDBD.
The diagonals of a rhombus bisect each other.
3
Calculate the half-diagonal length AOAO and full diagonal length ACAC.
AO=20AO = 20 and AC=40AC = 40.
The diagonals of a rhombus are perpendicular, forming right triangle AOBAOB. By the Pythagorean theorem, AO=AB2BO2=252152=20AO = \sqrt{AB^2 - BO^2} = \sqrt{25^2 - 15^2} = 20. Since the diagonals bisect each other, the total length of diagonal ACAC is 2×20=402 \times 20 = 40.
4
Determine the length of segment APAP.
AP=12AP = 12.
Point PP lies on diagonal ACAC such that the ratio of segment APAP to PCPC is 3:73:7. Therefore, AP=33+7×AC=310×40=12AP = \frac{3}{3+7} \times AC = \frac{3}{10} \times 40 = 12.
5
Find the distance OPOP between point PP and the intersection point OO.
OP=8OP = 8.
Since AO=20AO = 20 and PP is 1212 units from AA, PP lies on the segment AOAO. Thus, the distance from PP to OO is OP=AOAP=2012=8OP = AO - AP = 20 - 12 = 8.
6
Calculate the length of segment BPBP.
BP=17BP = 17.
Because the diagonals of a rhombus are perpendicular, BOP\triangle BOP is a right triangle with legs BO=15BO = 15 and OP=8OP = 8. Using the Pythagorean theorem, BP=BO2+OP2=152+82=17BP = \sqrt{BO^2 + OP^2} = \sqrt{15^2 + 8^2} = 17.

Key Concept

Properties of Rhombuses (perpendicular bisecting diagonals, equal side lengths) and the Pythagorean Theorem
Estimated Time:2m 0s
Question 2635Question

A circular garden plot has a radius of 10 meters10\text{ meters}. A sector of the garden with a central angle of 7272^\circ is planted with roses. What is the area, in square meters, of the sector planted with roses?

Show answer & explanation

Answer: 20π20\pi

Answer

The correct answer is 20π20\pi, representing the area of the sector in square meters.
The area of a sector of a circle is calculated using the formula Area=θ360πr2\text{Area} = \frac{\theta}{360^\circ} \pi r^2. Substituting θ=72\theta = 72^\circ and r=10 metersr = 10\text{ meters} gives 72360π(10)2=15100π=20π\frac{72^\circ}{360^\circ} \pi (10)^2 = \frac{1}{5} \cdot 100\pi = 20\pi.

Step-by-Step Solution

1
Identify the formula for the area of a sector.
Area=θ360πr2\text{Area} = \frac{\theta}{360^\circ} \pi r^2
The area of a sector is a proportional fraction of the total area of the circle.
2
Substitute the given values into the formula.
Area=72360π(10)2\text{Area} = \frac{72^\circ}{360^\circ} \pi (10)^2
The central angle is 7272^\circ and the radius is 10 meters10\text{ meters}.
3
Simplify the fraction and the squared term.
Area=15π(100)\text{Area} = \frac{1}{5} \pi (100)
72/36072/360 simplifies to 1/51/5 and 102=10010^2 = 100.
4
Perform the final multiplication.
20π20\pi
One-fifth of 100100 is 2020.

Key Concept

Calculating the area of a circle sector given the radius and the central angle in degrees.
Estimated Time:1m 0s
Question 2636Question

For a certain convex polygon, the ratio of the sum of the interior angles to the sum of the exterior angles is 5:15:1. How many sides does this polygon have?

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Answer: 12

Answer

The correct answer is 12 sides.
The sum of the interior angles of any convex polygon with nn sides is given by (n2)×180(n-2) \times 180^\circ. The sum of the exterior angles of any convex polygon is always 360360^\circ. Since the ratio of the sum of the interior angles to the sum of the exterior angles is 5:15:1, we can set up the equation: (n2)×180360=51\frac{(n-2) \times 180^\circ}{360^\circ} = \frac{5}{1}. Simplifying the fraction on the left gives n22=5\frac{n-2}{2} = 5. Multiplying both sides by 2 gives n2=10n - 2 = 10, and adding 2 to both sides gives n=12n = 12. Therefore, the polygon has 12 sides.

Step-by-Step Solution

1
Write the formulas for the sum of the interior angles and the sum of the exterior angles of a convex polygon.
The sum of the interior angles is (n2)×180(n-2) \times 180^\circ, where nn is the number of sides. The sum of the exterior angles is always 360360^\circ for any convex polygon.
These formulas represent the components of the given ratio.
2
Set up the ratio equation using the given information.
(n2)×180360=51\frac{(n-2) \times 180^\circ}{360^\circ} = \frac{5}{1}
The problem states that the ratio of the sum of the interior angles to the sum of the exterior angles is 5:15:1.
3
Simplify the equation and solve for the number of sides, nn.
n22=5    n2=10    n=12\frac{n-2}{2} = 5 \implies n-2 = 10 \implies n = 12
Simplifying 180360\frac{180}{360} to 12\frac{1}{2} makes it easier to solve the algebraic equation for nn.

Key Concept

The sum of the interior angles of a convex polygon with nn sides is (n2)×180(n-2) \times 180^\circ, while the sum of the exterior angles is always 360360^\circ.
Estimated Time:1m 30s
Question 2637Question

Match each of the trigonometric functions listed on the left with the correct description of its amplitude and period listed on the right.

Click a left item, then click its matching right item

Items

y=3sin(2x)y = 3\sin(2x)
y=2cos(3x)y = 2\cos(3x)
y=4sin(πx)y = 4\sin(\pi x)

Matches

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Answer

The function y=3sin(2x)y = 3\sin(2x) matches the description stating 'Amplitude is 3 and period is π\pi'. The function y=2cos(3x)y = 2\cos(3x) matches the description stating 'Amplitude is 2 and period is 2π3\frac{2\pi}{3}'. The function y=4sin(πx)y = 4\sin(\pi x) matches the description stating 'Amplitude is 4 and period is 2'.
Each trigonometric function of the form y=asin(bx)y = a\sin(bx) or y=acos(bx)y = a\cos(bx) has an amplitude equal to the absolute value of the coefficient of the trigonometric term (a|a|) and a period equal to 2π2\pi divided by the absolute value of the coefficient of the angle variable (b|b|). Applying these formulas gives the correct properties for each function.

Step-by-Step Solution

1
Identify the general form of the trigonometric functions
The functions are in the form y=asin(bx)y = a\sin(bx) or y=acos(bx)y = a\cos(bx), where the amplitude is given by the absolute value of the vertical stretch coefficient (a|a|), and the period is calculated as 2πb\frac{2\pi}{|b|}.
This establishes the formulas needed to determine the amplitude and period for each equation.
2
Calculate the properties for y=3sin(2x)y = 3\sin(2x)
The vertical stretch coefficient is 3, so the amplitude is 3. The frequency coefficient is 2, so the period is 2π2=π\frac{2\pi}{2} = \pi.
To find the amplitude and period for the first function.
3
Calculate the properties for y=2cos(3x)y = 2\cos(3x)
The vertical stretch coefficient is 2, so the amplitude is 2. The frequency coefficient is 3, so the period is 2π3\frac{2\pi}{3}.
To find the amplitude and period for the second function.
4
Calculate the properties for y=4sin(πx)y = 4\sin(\pi x)
The vertical stretch coefficient is 4, so the amplitude is 4. The frequency coefficient is π\pi, so the period is 2ππ=2\frac{2\pi}{\pi} = 2.
To find the amplitude and period for the third function.

Key Concept

Identifying the amplitude and calculating the period of trigonometric functions from their equations
Estimated Time:1m 30s
Question 2638Question

In the standard (x,y)(x, y) coordinate plane, three vertices of a rectangle are A(4,1)A(-4, 1), B(2,9)B(2, 9), and C(6,6)C(6, 6). What is the area of the rectangle, in square units?

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Answer: 50

Answer

50
The length of side ABAB is calculated as (2(4))2+(91)2=36+64=10\sqrt{(2 - (-4))^2 + (9 - 1)^2} = \sqrt{36 + 64} = 10. The length of the adjacent side BCBC is calculated as (62)2+(69)2=16+9=5\sqrt{(6 - 2)^2 + (6 - 9)^2} = \sqrt{16 + 9} = 5. The area of the rectangle is the product of these two perpendicular side lengths, which is 10×5=5010 \times 5 = 50.

Step-by-Step Solution

1
Calculate the length of side ABAB using the distance formula.
AB=10AB = 10
To find one of the side lengths of the rectangle.
2
Calculate the length of side BCBC using the distance formula.
BC=5BC = 5
To find the adjacent side length of the rectangle.
3
Multiply the two adjacent side lengths to find the area of the rectangle.
50
The area of a rectangle is equal to the product of its length and width.

Key Concept

Calculating the area of a geometric figure on the coordinate plane by determining its side lengths using the distance formula.
Question 2639Question

A commercial drone starts at an altitude of 150150 meters and descends at a constant rate. After 1212 seconds of descent, its altitude is 114114 meters. If the altitude, aa, in meters, is modeled as a linear function of time, tt, in seconds, what is the slope of the line representing this relationship in the standard (t,a)(t, a) coordinate plane?

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Answer: 3-3

Answer

The slope of the line representing this relationship is 3-3.
The slope of the line represents the rate of change of the altitude with respect to time. By taking the initial point (0,150)(0, 150) and the point after 1212 seconds (12,114)(12, 114), the change in altitude is 114150=36114 - 150 = -36 meters. Dividing this by the change in time of 120=1212 - 0 = 12 seconds yields the correct slope of 3-3.

Step-by-Step Solution

1
Identify the coordinate points (t,a)(t, a) from the given information.
The initial state corresponds to the point (0,150)(0, 150), and the state after 1212 seconds corresponds to (12,114)(12, 114).
Setting up coordinate pairs allows the direct application of the slope formula.
2
Apply the slope formula m=a2a1t2t1m = \frac{a_2 - a_1}{t_2 - t_1} to find the rate of change.
m=114150120m = \frac{114 - 150}{12 - 0}
The slope is the change in the vertical variable (altitude) divided by the change in the horizontal variable (time).
3
Calculate the difference and simplify the fraction.
m=3612=3m = \frac{-36}{12} = -3
Subtracting 150150 from 114114 gives the net change in altitude, which when divided by the duration of 1212 seconds yields the rate of change per second.

Key Concept

The slope of a line represents its constant rate of change, defined as the ratio of the change in the dependent variable to the change in the independent variable.
Question 2640Question

What are the solutions for xx in the quadratic equation 0.2x20.6x+2.2=00.2x^2 - 0.6x + 2.2 = 0?

Show answer & explanation

Answer: 3±i352\frac{3 \pm i\sqrt{35}}{2}

Answer

The correct answer is 3±i352\frac{3 \pm i\sqrt{35}}{2}.
The correct answer is the pair of complex solutions 3±i352\frac{3 \pm i\sqrt{35}}{2}. By multiplying the equation 0.2x20.6x+2.2=00.2x^2 - 0.6x + 2.2 = 0 by 55, we get the equivalent equation with integer coefficients, x23x+11=0x^2 - 3x + 11 = 0. Applying the quadratic formula with a=1a = 1, b=3b = -3, and c=11c = 11 yields a discriminant of 944=359 - 44 = -35. Since the discriminant is negative, the solutions are complex: 3±i352\frac{3 \pm i\sqrt{35}}{2}.

Step-by-Step Solution

1
Multiply both sides of the quadratic equation by 55 to eliminate the decimal coefficients.
The equation 0.2x20.6x+2.2=00.2x^2 - 0.6x + 2.2 = 0 becomes x23x+11=0x^2 - 3x + 11 = 0.
Working with integer coefficients simplifies algebraic manipulation and reduces the risk of calculation errors.
2
Identify the coefficients aa, bb, and cc in the standard quadratic form ax2+bx+c=0ax^2 + bx + c = 0.
a=1a = 1, b=3b = -3, and c=11c = 11.
These values are required to apply the quadratic formula.
3
Substitute the coefficients into the quadratic formula, x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}.
x=(3)±(3)24(1)(11)2(1)=3±9442=3±352x = \frac{-(-3) \pm \sqrt{(-3)^2 - 4(1)(11)}}{2(1)} = \frac{3 \pm \sqrt{9 - 44}}{2} = \frac{3 \pm \sqrt{-35}}{2}.
The quadratic formula provides the exact solutions for any quadratic equation.
4
Simplify the radical using the imaginary unit, i=1i = \sqrt{-1}.
35=351=i35\sqrt{-35} = \sqrt{35} \cdot \sqrt{-1} = i\sqrt{35}, so the solutions are x=3±i352x = \frac{3 \pm i\sqrt{35}}{2}.
Standard mathematical notation represents the square root of a negative number using ii.

Key Concept

Using the quadratic formula to solve quadratic equations with decimal coefficients and complex roots.
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