Geometry

156 questions

Question 41Question

In a geometric plane, straight lines L1L_1 and L2L_2 intersect at point PP. The measure of the obtuse angle formed by the intersection of L1L_1 and L2L_2 is (5x10)(5x - 10)^\circ, and the measure of an adjacent acute angle is (2x+15)(2x + 15)^\circ. Ray PQPQ originates from point PP, is perpendicular to line L1L_1, and lies entirely within the interior of the (5x10)(5x - 10)^\circ obtuse angle. What is the measure, in degrees, of the angle formed between ray PQPQ and line L2L_2?

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Answer: 2525^\circ

Answer

2525^\circ
Two intersecting lines form adjacent angles that sum to 180180^\circ. Solving (5x10)+(2x+15)=180(5x - 10) + (2x + 15) = 180 gives 7x+5=1807x + 5 = 180, so x=25x = 25. The obtuse angle measure is 5(25)10=1155(25) - 10 = 115^\circ. Since ray PQPQ is perpendicular to line L1L_1, it forms a 9090^\circ angle with line L1L_1. The remaining angle between ray PQPQ and line L2L_2 within the obtuse angle region is 11590=25115^\circ - 90^\circ = 25^\circ.

Step-by-Step Solution

1
Set up an algebraic equation using the supplementary angle relationship.
(5x10)+(2x+15)=180(5x - 10) + (2x + 15) = 180
Adjacent angles formed by two intersecting straight lines lie on a straight line and are supplementary, summing to 180180^\circ.
2
Solve for the variable xx.
7x+5=180    7x=175    x=257x + 5 = 180 \implies 7x = 175 \implies x = 25
Combining like terms simplifies the linear equation.
3
Calculate the degree measure of the obtuse angle.
Obtuse angle = 5(25)10=12510=1155(25) - 10 = 125 - 10 = 115^\circ
Substitute x=25x = 25 back into the expression (5x10)(5x - 10)^\circ.
4
Calculate the angle between ray PQPQ and line L2L_2.
Angle = 11590=25115^\circ - 90^\circ = 25^\circ
Ray PQPQ is perpendicular to line L1L_1 (9090^\circ) and lies inside the 115115^\circ angle, dividing the obtuse angle into a 9090^\circ portion and the remaining angle adjacent to line L2L_2.

Key Concept

Supplementary angles on a straight line and angle subtraction with perpendicular rays
Estimated Time:1m 30s
Question 42Question

A sector of a circle has an area of 15π15\pi square units and a perimeter of 10+6π10 + 6\pi units. What is the measure of the central angle of the sector, in degrees?

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Answer: 216216^\circ

Answer

The correct answer is 216216^\circ, corresponding to the option stating 216216^\circ.
The perimeter of a sector is defined as 2r+s=10+6π2r + s = 10 + 6\pi, which yields a radius of r=5r = 5 and an arc length s=6πs = 6\pi. Checking with the sector area formula 12rs=12(5)(6π)=15π\frac{1}{2}rs = \frac{1}{2}(5)(6\pi) = 15\pi confirms these measurements. The total area of the circle is π(5)2=25π\pi (5)^2 = 25\pi. The sector thus constitutes 15π25π=35\frac{15\pi}{25\pi} = \frac{3}{5} of the circle. Multiplying this fraction by 360360^\circ gives a central angle of 216216^\circ.

Step-by-Step Solution

1
Express the sector perimeter formula and solve for radius and arc length.
Radius r=5r = 5 and arc length s=6πs = 6\pi.
The perimeter of a sector equals two radii plus its arc length: Perimeter=2r+s=10+6π\text{Perimeter} = 2r + s = 10 + 6\pi. Equating standard and π\pi-termed components gives 2r=10    r=52r = 10 \implies r = 5 and arc length s=6πs = 6\pi.
2
Verify consistency using the sector area formula.
Area=15π\text{Area} = 15\pi, matching the given information.
The area of a sector can also be calculated as 12rs=12(5)(6π)=15π\frac{1}{2} r s = \frac{1}{2}(5)(6\pi) = 15\pi.
3
Find the total area of the circle and the fraction of the circle occupied by the sector.
Total area =25π= 25\pi, area fraction =35= \frac{3}{5}.
The full circle area is πr2=π(52)=25π\pi r^2 = \pi (5^2) = 25\pi. The sector represents 15π25π=35\frac{15\pi}{25\pi} = \frac{3}{5} of the entire circle.
4
Calculate the central angle θ\theta in degrees.
θ=216\theta = 216^\circ.
Multiply the fraction by 360360^\circ: θ=35×360=216\theta = \frac{3}{5} \times 360^\circ = 216^\circ.

Key Concept

Perimeter, Arc Length, and Area of a Circle Sector
Question 43Question

In a circle centered at point OO with radius RR, radii OAOA and OBOB bound a sector AOBAOB with a central angle of 120120^\circ. Point PP lies on minor arc ABAB such that the ratio of the length of arc APAP to the length of arc PBPB is 1:31:3. Segment PQPQ is drawn perpendicular to radius OAOA, intersecting OAOA at point QQ. What is the ratio of the area of the region bounded by line segment PQPQ, line segment AQAQ, and minor arc APAP to the area of sector AOBAOB?

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Answer: 4π3316π\frac{4\pi - 3\sqrt{3}}{16\pi}

Answer

4π3316π\frac{4\pi - 3\sqrt{3}}{16\pi}
The correct answer 4π3316π\frac{4\pi - 3\sqrt{3}}{16\pi} is obtained by finding the central angle of sector AOPAOP (3030^\circ), subtracting the area of right triangle OQPOQP (316R2\frac{\sqrt{3}}{16}R^2) from the area of sector AOPAOP (π12R2\frac{\pi}{12}R^2), and dividing this bounded area by the total sector AOBAOB area (π3R2\frac{\pi}{3}R^2).

Step-by-Step Solution

1
Determine the central angle AOP\angle AOP of sector AOPAOP
AOP=11+3×120=30\angle AOP = \frac{1}{1+3} \times 120^\circ = 30^\circ
Arc length is directly proportional to central angle. A 1:31:3 ratio means sector AOPAOP represents 14\frac{1}{4} of the 120120^\circ central angle.
2
Calculate the area of sector AOPAOP and the total area of sector AOBAOB
Area(Sector AOP)=30360πR2=π12R2\text{Area(Sector } AOP) = \frac{30^\circ}{360^\circ} \pi R^2 = \frac{\pi}{12} R^2, and Area(Sector AOB)=120360πR2=π3R2\text{Area(Sector } AOB) = \frac{120^\circ}{360^\circ} \pi R^2 = \frac{\pi}{3} R^2
The area of a sector with central angle θ\theta is θ360πR2\frac{\theta}{360^\circ} \pi R^2.
3
Calculate the area of right triangle OQPOQP
Area(OQP)=316R2\text{Area}(\triangle OQP) = \frac{\sqrt{3}}{16} R^2
In OQP\triangle OQP, QOP=30\angle QOP = 30^\circ and hypotenuse OP=ROP = R. Thus OQ=Rcos(30)=R32OQ = R \cos(30^\circ) = \frac{R\sqrt{3}}{2} and PQ=Rsin(30)=R2PQ = R \sin(30^\circ) = \frac{R}{2}. Area=12×OQ×PQ=12(R32)(R2)=316R2\text{Area} = \frac{1}{2} \times OQ \times PQ = \frac{1}{2} \left(\frac{R\sqrt{3}}{2}\right)\left(\frac{R}{2}\right) = \frac{\sqrt{3}}{16} R^2.
4
Calculate the area of the bounded region and take the ratio to the area of sector AOBAOB
Ratio=π12R2316R2π3R2=4π3316π\text{Ratio} = \frac{\frac{\pi}{12}R^2 - \frac{\sqrt{3}}{16}R^2}{\frac{\pi}{3}R^2} = \frac{4\pi - 3\sqrt{3}}{16\pi}
Subtract the triangle area from sector AOPAOP area to get the bounded region area, then divide by sector AOBAOB area.

Key Concept

Sector Area, Arc Length Proportions, and Geometric Region Subdivision
Estimated Time:3m 0s
Question 44Question

Two concentric circles centered at point OO have radii rr and RR, where r<Rr < R. A sector bounded by radii OAOA and OBOB of the outer circle has central angle θ\theta^\circ. Region SS is the region lying inside sector AOBAOB but outside the inner circle. The area of region SS is equal to 33 times the area of the sector of the inner circle bounded by central angle θ\theta^\circ. If the perimeter of region SS is equal to 116\frac{11}{6} times the length of arc ABAB, what is the value of θ\theta?

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Answer: 540π\frac{540}{\pi}

Answer

540π\frac{540}{\pi}
The area of region SS is θ360π(R2r2)\frac{\theta}{360}\pi(R^2 - r^2), which is equal to 33 times the area of the inner sector θ360πr2\frac{\theta}{360}\pi r^2. This simplifies to R2r2=3r2    R=2rR^2 - r^2 = 3r^2 \implies R = 2r. The perimeter of region SS consists of outer arc length LouterL_{\text{outer}}, inner arc length Linner=12LouterL_{\text{inner}} = \frac{1}{2} L_{\text{outer}}, and two straight line segments each of length Rr=rR - r = r. Setting the total perimeter 32Louter+2r\frac{3}{2} L_{\text{outer}} + 2r equal to 116Louter\frac{11}{6} L_{\text{outer}} yields 2r=13Louter2r = \frac{1}{3} L_{\text{outer}}, or Louter=6rL_{\text{outer}} = 6r. Substituting Louter=θ360(2πR)=4πrθ360L_{\text{outer}} = \frac{\theta}{360}(2\pi R) = \frac{4\pi r \theta}{360} gives 4πrθ360=6r\frac{4\pi r \theta}{360} = 6r, which solves to θ=540π\theta = \frac{540}{\pi}.

Step-by-Step Solution

1
Relate outer radius RR to inner radius rr using sector areas.
R=2rR = 2r
The area of region SS is θ360π(R2r2)\frac{\theta}{360}\pi(R^2 - r^2) and the inner sector area is θ360πr2\frac{\theta}{360}\pi r^2. Setting θ360π(R2r2)=3θ360πr2\frac{\theta}{360}\pi(R^2 - r^2) = 3 \cdot \frac{\theta}{360}\pi r^2 gives R2r2=3r2R^2 - r^2 = 3r^2, so R2=4r2R^2 = 4r^2 and R=2rR = 2r.
2
Express the perimeter of region SS in terms of outer arc length LouterL_{\text{outer}} and radius rr.
Perimeter(S)=32Louter+2r\text{Perimeter}(S) = \frac{3}{2} L_{\text{outer}} + 2r
Region SS is bounded by outer arc ABAB (LouterL_{\text{outer}}), inner arc CDCD (LinnerL_{\text{inner}}), and two straight segments ACAC and BDBD of length Rr=2rr=rR - r = 2r - r = r. Since R=2rR = 2r, Linner=12LouterL_{\text{inner}} = \frac{1}{2} L_{\text{outer}}, making total perimeter Louter+12Louter+2(r)=32Louter+2rL_{\text{outer}} + \frac{1}{2} L_{\text{outer}} + 2(r) = \frac{3}{2} L_{\text{outer}} + 2r.
3
Use the given perimeter relationship to express LouterL_{\text{outer}} in terms of rr.
Louter=6rL_{\text{outer}} = 6r
Setting 32Louter+2r=116Louter\frac{3}{2} L_{\text{outer}} + 2r = \frac{11}{6} L_{\text{outer}} yields 2r=(11696)Louter=13Louter2r = \left(\frac{11}{6} - \frac{9}{6}\right) L_{\text{outer}} = \frac{1}{3} L_{\text{outer}}, so Louter=6rL_{\text{outer}} = 6r.
4
Solve for θ\theta using the definition of outer arc length.
θ=540π\theta = \frac{540}{\pi}
Louter=θ360(2πR)=θ360(4πr)L_{\text{outer}} = \frac{\theta}{360}(2\pi R) = \frac{\theta}{360}(4\pi r). Setting 4πrθ360=6r\frac{4\pi r \theta}{360} = 6r simplifies to πθ90=6\frac{\pi \theta}{90} = 6, giving θ=540π\theta = \frac{540}{\pi}.

Key Concept

Annular sector area and perimeter relations combining arc length formulas and concentric circle geometry.
Estimated Time:2m 30s
Question 45Question

A circle has a radius of 99 inches. What is the area, in square inches, of a sector of this circle formed by a central angle of 4040^\circ?

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Answer: 9π9\pi

Answer

The area of the sector is 9π9\pi square inches.
The area of a sector with radius rr and central angle θ\theta is calculated as Area=πr2(θ360)\text{Area} = \pi r^2 \left(\frac{\theta}{360^\circ}\right). Substituting r=9r = 9 and θ=40\theta = 40^\circ yields π(92)(40360)=81π(19)=9π\pi (9^2) \left(\frac{40^\circ}{360^\circ}\right) = 81\pi \left(\frac{1}{9}\right) = 9\pi square inches.

Step-by-Step Solution

1
Calculate the area of the entire circle using the formula Acircle=πr2A_{\text{circle}} = \pi r^2.
Acircle=π(92)=81πA_{\text{circle}} = \pi (9^2) = 81\pi square inches.
The full circle area provides the total measure from which the sector fraction is calculated.
2
Determine the fraction of the circle represented by the central angle of 4040^\circ.
40360=19\frac{40^\circ}{360^\circ} = \frac{1}{9}.
A circle contains 360360^\circ in total, so the central angle over 360360^\circ gives the proportion of the circle covered by the sector.
3
Multiply the total area of the circle by the fraction of the sector.
Sector Area=81π×19=9π\text{Sector Area} = 81\pi \times \frac{1}{9} = 9\pi square inches.
Applying the fraction to the total area yields the specific sector area.

Key Concept

Sector Area of a Circle
Question 46Question

Circle C1C_1 has radius r1r_1 and Circle C2C_2 has radius r2r_2. An arc on Circle C1C_1 subtended by a central angle of θ1\theta_1^\circ has the exact same length as an arc on Circle C2C_2 subtended by a central angle of θ2\theta_2^\circ. The sector formed by this arc in Circle C1C_1 has an area of 54π54\pi, and the sector formed by this arc in Circle C2C_2 has an area of 36π36\pi. If θ1+θ2=150\theta_1 + \theta_2 = 150, what is the value of r1r_1?

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Answer: 18

Answer

The radius r1r_1 of Circle C1C_1 is 18.
Using the relationship A=12LrA = \frac{1}{2} L r, the ratio of the two sector areas gives r1r2=54π36π=1.5\frac{r_1}{r_2} = \frac{54\pi}{36\pi} = 1.5, so r2=23r1r_2 = \frac{2}{3} r_1. Expressing arc length as L=108πr1L = \frac{108\pi}{r_1}, the central angles are θ1=19440r12\theta_1 = \frac{19440}{r_1^2} and θ2=29160r12\theta_2 = \frac{29160}{r_1^2}. Setting their sum equal to 150150 leads to 48600r12=150\frac{48600}{r_1^2} = 150, giving r12=324r_1^2 = 324 and r1=18r_1 = 18.

Step-by-Step Solution

1
Relate sector area to arc length and radius
A1=12Lr1=54πA_1 = \frac{1}{2} L r_1 = 54\pi and A2=12Lr2=36πA_2 = \frac{1}{2} L r_2 = 36\pi
The area of a sector with arc length LL and radius rr is given by A=θ360πr2=12LrA = \frac{\theta}{360}\pi r^2 = \frac{1}{2} L r.
2
Find the ratio of r1r_1 to r2r_2
r1r2=54π36π=32    r2=23r1\frac{r_1}{r_2} = \frac{54\pi}{36\pi} = \frac{3}{2} \implies r_2 = \frac{2}{3}r_1
Dividing the first area equation by the second cancels out 12L\frac{1}{2}L.
3
Express central angles in terms of r1r_1
θ1=19440r12\theta_1 = \frac{19440}{r_1^2} and θ2=29160r12\theta_2 = \frac{29160}{r_1^2}
Since L=108πr1L = \frac{108\pi}{r_1}, substituting into θ1=L2πr1×360\theta_1 = \frac{L}{2\pi r_1} \times 360 yields θ1=19440r12\theta_1 = \frac{19440}{r_1^2}, and substituting into θ2=L2π(23r1)×360\theta_2 = \frac{L}{2\pi (\frac{2}{3}r_1)} \times 360 yields θ2=29160r12\theta_2 = \frac{29160}{r_1^2}.
4
Solve for r1r_1 using the angle sum equation
r1=18r_1 = 18
Summing the angles gives 19440+29160r12=48600r12=150    r12=324    r1=18\frac{19440 + 29160}{r_1^2} = \frac{48600}{r_1^2} = 150 \implies r_1^2 = 324 \implies r_1 = 18.

Key Concept

Relationship between arc length, radius, central angle, and sector area
Estimated Time:2m 30s
Question 47Question

In triangle ABCABC, the measure of angle AA is 4040^\circ and the measure of angle BB is 7070^\circ. If the perimeter of triangle ABCABC is 2222 centimeters and the length of side ABAB is 88 centimeters, what is the length, in centimeters, of side BCBC?

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Answer: 66

Answer

6 centimeters
First, find the measure of angle CC: 1804070=70180^\circ - 40^\circ - 70^\circ = 70^\circ. Because angle BB and angle CC both measure 7070^\circ, triangle ABCABC is isosceles with sides ACAC and ABAB of equal length (AC=AB=8AC = AB = 8 cm). Since the perimeter is the sum of all three sides (AB+AC+BC=22AB + AC + BC = 22), substituting the known side lengths gives 8+8+BC=228 + 8 + BC = 22, which yields BC=6BC = 6 cm.

Step-by-Step Solution

1
Calculate the measure of the third angle, angle CC.
Angle C=180(40+70)=70C = 180^\circ - (40^\circ + 70^\circ) = 70^\circ.
The sum of interior angles in any triangle is 180180^\circ.
2
Determine the relationship between the side lengths using the angle measures.
Side AC=AB=8AC = AB = 8 centimeters.
Since angle B=70B = 70^\circ and angle C=70C = 70^\circ, triangle ABCABC is isosceles. Sides opposite equal angles are equal in length, so the side opposite angle CC (which is ABAB) equals the side opposite angle BB (which is ACAC).
3
Use the perimeter formula to find the length of side BCBC.
Length of side BC=22(8+8)=6BC = 22 - (8 + 8) = 6 centimeters.
Perimeter is the total boundary distance (AB+AC+BC=22AB + AC + BC = 22). Substituting known values gives 8+8+BC=228 + 8 + BC = 22, so BC=6BC = 6.

Key Concept

Isosceles Triangle Side-Angle Properties and Perimeter
Estimated Time:45s
Question 48Question

Lines L1L_1 and L2L_2 intersect at point PP to form an acute angle of 5454^\circ. Line MM passes through point PP and is perpendicular to line L1L_1. Ray RR originates at point PP and lies in the interior of one of the obtuse angles formed by L1L_1 and L2L_2. If Ray RR bisects the angle formed between line MM and line L2L_2, what is the measure, in degrees, of the acute angle formed by Ray RR and line L1L_1?

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Answer: 72

Answer

The measure of the acute angle formed by Ray RR and line L1L_1 is 7272^\circ.
Lines L1L_1 and L2L_2 form an obtuse angle of 18054=126180^\circ - 54^\circ = 126^\circ. Perpendicular line MM consumes 9090^\circ of this angle relative to L1L_1, leaving 3636^\circ between line MM and line L2L_2. Bisecting this remaining angle gives 1818^\circ. Ray RR therefore lies 1818^\circ away from perpendicular line MM, making an acute angle of 9018=7290^\circ - 18^\circ = 72^\circ with line L1L_1.

Step-by-Step Solution

1
Determine the measure of the obtuse angle between lines L1L_1 and L2L_2.
The obtuse angle measures 18054=126180^\circ - 54^\circ = 126^\circ.
Adjacent angles along intersecting straight lines are supplementary and sum to 180180^\circ.
2
Find the angle between perpendicular line MM and line L2L_2.
The angle between line MM and line L2L_2 within the obtuse region is 12690=36126^\circ - 90^\circ = 36^\circ.
Line MM is perpendicular to line L1L_1, taking up 9090^\circ of the 126126^\circ obtuse angle.
3
Determine the angle formed by Ray RR after bisecting the 3636^\circ angle.
The angle between Ray RR and line MM is 36/2=1836^\circ / 2 = 18^\circ.
An angle bisector divides an angle into two equal parts.
4
Calculate the acute angle between Ray RR and line L1L_1.
The acute angle formed between Ray RR and line L1L_1 is 9018=7290^\circ - 18^\circ = 72^\circ.
Line MM forms a 9090^\circ angle with line L1L_1. Subtracting the 1818^\circ offset created by Ray RR yields the acute angle of 7272^\circ.

Key Concept

Supplementary angles, perpendicular lines, and angle bisectors
Estimated Time:2m 0s
Question 49Question

A right circular cylinder has a base radius of 33 units and a height of 44 units. Which of the following statements regarding this cylinder are true? Select all such statements.

Select all that apply

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Answer: The volume of the cylinder is 36π36\pi cubic units.; The total surface area of the cylinder is 42π42\pi square units.

Answer

The correct statements are that the volume of the cylinder is 36π36\pi cubic units and the total surface area of the cylinder is 42π42\pi square units.
The volume of a cylinder with radius 33 and height 44 is V=πr2h=π(3)2(4)=36πV = \pi r^2 h = \pi(3)^2(4) = 36\pi. The total surface area is A=2πrh+2πr2=2π(3)(4)+2π(3)2=24π+18π=42πA = 2\pi r h + 2\pi r^2 = 2\pi(3)(4) + 2\pi(3)^2 = 24\pi + 18\pi = 42\pi. Therefore, both statements asserting these exact values are correct.

Step-by-Step Solution

1
Calculate the volume of the right circular cylinder
Volume V=πr2h=π(32)(4)=36πV = \pi r^2 h = \pi (3^2)(4) = 36\pi
The formula for the volume of a right circular cylinder is V=πr2hV = \pi r^2 h.
2
Calculate the lateral surface area and total surface area of the cylinder
Lateral Area = 2πrh=24π2\pi r h = 24\pi; Total Area = 24π+2(π32)=42π24\pi + 2(\pi \cdot 3^2) = 42\pi
Total surface area is the sum of the lateral surface area (2πrh2\pi r h) and the areas of the two circular bases (2πr22\pi r^2).
3
Evaluate the base-to-lateral surface area ratio
Ratio = 9π24π=38\frac{9\pi}{24\pi} = \frac{3}{8}
Comparing the base area (9π9\pi) to the lateral area (24π24\pi) simplifies to 3:83:8.

Key Concept

Volume and surface area formulas for right circular cylinders
Question 50Question

In the geometric plane, line kk is parallel to line mm (kmk \parallel m). Transversal line tt intersects line kk at point AA and line mm at point BB. Point CC lies on line kk to the left of AA, such that interior acute angle CAB=(3x10)\angle CAB = (3x - 10)^\circ. Ray ADAD bisects CAB\angle CAB. Ray BFBF is drawn into the region between lines kk and mm making an angle ABF=(x+35)\angle ABF = (x + 35)^\circ with transversal segment ABAB. Ray ADAD and ray BFBF intersect at point PP inside the parallel region. Line PBPB is extended past PP to intersect line kk at point QQ. If ray ADAD is perpendicular to ray BFBF, what is the measure of the obtuse angle formed at the intersection of line QBQB and line kk?

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Answer: 121121^\circ

Answer

The measure of the obtuse angle formed at the intersection of line QBQB and line kk is 121121^\circ.
The measure 121121^\circ is correct because ray ADAD bisects CAB\angle CAB, giving PAB=(1.5x5)\angle PAB = (1.5x - 5)^\circ. Since ADBFAD \perp BF, APB\triangle APB is a right triangle where (1.5x5)+(x+35)=90(1.5x - 5) + (x + 35) = 90, yielding x=24x = 24. Consequently, QAB=62\angle QAB = 62^\circ and ABQ=59\angle ABQ = 59^\circ. In ABQ\triangle ABQ, the acute angle AQB=180(62+59)=59\angle AQB = 180^\circ - (62^\circ + 59^\circ) = 59^\circ. The supplementary obtuse angle along line kk is 18059=121180^\circ - 59^\circ = 121^\circ.

Step-by-Step Solution

1
Express the angle PAB\angle PAB in terms of xx.
Since ray ADAD bisects CAB=(3x10)\angle CAB = (3x - 10)^\circ, PAB=3x102=(1.5x5)\angle PAB = \frac{3x - 10}{2} = (1.5x - 5)^\circ.
An angle bisector divides an angle into two equal halves.
2
Set up an equation using triangle APB\triangle APB.
In APB\triangle APB, APB=90\angle APB = 90^\circ because ray ADAD \perp ray BFBF. Therefore, PAB+ABP=90    (1.5x5)+(x+35)=90    2.5x+30=90    2.5x=60    x=24\angle PAB + \angle ABP = 90^\circ \implies (1.5x - 5) + (x + 35) = 90 \implies 2.5x + 30 = 90 \implies 2.5x = 60 \implies x = 24.
The acute angles in a right triangle sum to 9090^\circ.
3
Calculate the measures of CAB\angle CAB and ABQ\angle ABQ.
CAB=3(24)10=62\angle CAB = 3(24) - 10 = 62^\circ, and ABQ=ABF=24+35=59\angle ABQ = \angle ABF = 24 + 35 = 59^\circ.
Substitute x=24x = 24 back into the original angle expressions.
4
Determine the acute angle AQB\angle AQB in triangle ABQ\triangle ABQ.
In ABQ\triangle ABQ, points Q,C,AQ, C, A lie on line kk, so QAB=CAB=62\angle QAB = \angle CAB = 62^\circ. Sum of angles in ABQ\triangle ABQ: AQB=180(62+59)=180121=59\angle AQB = 180^\circ - (62^\circ + 59^\circ) = 180^\circ - 121^\circ = 59^\circ.
The interior angles of any triangle sum to 180180^\circ.
5
Find the supplementary obtuse angle at intersection point QQ.
Obtuse angle =18059=121= 180^\circ - 59^\circ = 121^\circ.
Angles forming a linear pair on a straight line are supplementary.

Key Concept

Parallel Lines, Transversals, Angle Bisectors, and Triangle Angle Sum Theorem
Question 51Question

A square is inscribed in a circle with center OO. The perimeter of the square is 16216\sqrt{2} units. A sector of this circle has an area equal to the total area of the region inside the circle that lies outside the square. What is the arc length of this sector?

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Answer: 8π168\pi - 16

Answer

8π168\pi - 16
The correct answer is 8π168\pi - 16. The inscribed square has side length 424\sqrt{2} and diagonal 88. Since the diagonal of an inscribed square is the circle's diameter, the circle has radius r=4r = 4 and total area 16π16\pi. The square has area 3232, so the region outside the square has area 16π3216\pi - 32. For any sector of radius rr, the arc length LL and sector area AA satisfy L=2ArL = \frac{2A}{r}. Substituting A=16π32A = 16\pi - 32 and r=4r = 4 yields L=2(16π32)4=8π16L = \frac{2(16\pi - 32)}{4} = 8\pi - 16.

Step-by-Step Solution

1
Find the side length and diagonal of the inscribed square.
Side length s=1624=42s = \frac{16\sqrt{2}}{4} = 4\sqrt{2}. Diagonal d=s2=(42)2=8d = s\sqrt{2} = (4\sqrt{2})\sqrt{2} = 8.
The perimeter of a square is 4s4s, and the diagonal of a square with side ss is s2s\sqrt{2}.
2
Determine the radius and total area of the circle.
Diameter equals diagonal d=8d = 8, so radius r=4r = 4. Area of circle Acircle=πr2=16πA_{\text{circle}} = \pi r^2 = 16\pi.
A square inscribed in a circle has its diagonal aligned with the diameter of the circle.
3
Calculate the area of the region inside the circle but outside the square.
Area of square Asquare=(42)2=32A_{\text{square}} = (4\sqrt{2})^2 = 32. Area outside square Aoutside=16π32A_{\text{outside}} = 16\pi - 32.
Subtract the area of the inscribed square from the total area of the circle.
4
Relate sector area to arc length using L=2AsectorrL = \frac{2 A_{\text{sector}}}{r}.
L=2(16π32)4=32π644=8π16L = \frac{2(16\pi - 32)}{4} = \frac{32\pi - 64}{4} = 8\pi - 16.
Since sector area Asector=θ360πr2A_{\text{sector}} = \frac{\theta}{360^\circ}\pi r^2 and arc length L=θ360(2πr)L = \frac{\theta}{360^\circ}(2\pi r), we have L=2AsectorrL = \frac{2A_{\text{sector}}}{r}.

Key Concept

Relationship between circle area, inscribed figures, sector area, and arc length
Estimated Time:1m 30s
Question 52Question

Four rays, OA\vec{OA}, OB\vec{OB}, OC\vec{OC}, and OD\vec{OD}, radiate from a common point OO in consecutive clockwise order such that OAOC\vec{OA} \perp \vec{OC} and OBOD\vec{OB} \perp \vec{OD}. If the measure of angle AOD\angle AOD is 3.53.5 times the measure of angle BOC\angle BOC, what is the measure, in degrees, of angle AOB\angle AOB?

Show answer & explanation

Answer: 5050^\circ

Answer

5050^\circ
Because OAOC\vec{OA} \perp \vec{OC} and OBOD\vec{OB} \perp \vec{OD}, we know AOB+BOC=90\angle AOB + \angle BOC = 90^\circ and BOC+COD=90\angle BOC + \angle COD = 90^\circ, which implies AOB=COD\angle AOB = \angle COD. The total angle AOD=AOB+BOD=AOB+90\angle AOD = \angle AOB + \angle BOD = \angle AOB + 90^\circ. Using the given condition AOD=3.5×BOC\angle AOD = 3.5 \times \angle BOC, we substitute BOC=90AOB\angle BOC = 90^\circ - \angle AOB to get AOB+90=3.5(90AOB)\angle AOB + 90^\circ = 3.5(90^\circ - \angle AOB), which solves to AOB=50\angle AOB = 50^\circ.

Step-by-Step Solution

1
Set up angle variable definitions and perpendicular relationships.
Let AOB=x\angle AOB = x, BOC=y\angle BOC = y, and COD=z\angle COD = z. Since OAOC\vec{OA} \perp \vec{OC}, we have x+y=90x + y = 90^\circ. Since OBOD\vec{OB} \perp \vec{OD}, we have y+z=90y + z = 90^\circ.
Perpendicular rays form right angles measuring 9090^\circ.
2
Deduce the relationship between xx, yy, and zz, and express AOD\angle AOD in terms of xx.
Subtracting yy from both equations gives x=90yx = 90^\circ - y and z=90yz = 90^\circ - y, so x=zx = z. Thus, AOD=x+y+z=x+90\angle AOD = x + y + z = x + 90^\circ.
Adjacent angles sharing a vertex add up to form the overall combined angle.
3
Formulate and solve the equation based on the given ratio.
We are given AOD=3.5×BOC\angle AOD = 3.5 \times \angle BOC, so x+90=3.5yx + 90^\circ = 3.5y. Substituting y=90xy = 90^\circ - x yields x+90=3.5(90x)    x+90=3153.5x    4.5x=225    x=50x + 90^\circ = 3.5(90^\circ - x) \implies x + 90^\circ = 315^\circ - 3.5x \implies 4.5x = 225^\circ \implies x = 50^\circ.
Substitution creates a single linear equation in terms of x=AOBx = \angle AOB.

Key Concept

Perpendicular Ray Systems and Angle Addition
Estimated Time:1m 30s
Question 53Question

In circle OO, minor arc ABAB is subtended by a central angle of 120120^\circ, and the radius of circle OO is 66. A smaller circle, circle CC, is constructed such that it is tangent to chord ABAB at its midpoint and tangent to minor arc ABAB at its midpoint. What is the area of a sector of circle CC subtended by a central angle of 9090^\circ?

Show answer & explanation

Answer: 9π16\frac{9\pi}{16}

Answer

9π16\frac{9\pi}{16}
The distance from the center of circle OO to chord ABAB is 6cos(60)=36 \cos(60^\circ) = 3, leaving a height of 63=36 - 3 = 3 for the minor segment. Circle CC is tangent to the chord and arc midpoints, making its diameter equal to 33 and its radius 32\frac{3}{2}. The area of a 9090^\circ sector of circle CC is 90360π(32)2=9π16\frac{90^\circ}{360^\circ} \pi \left(\frac{3}{2}\right)^2 = \frac{9\pi}{16}.

Step-by-Step Solution

1
Find the perpendicular distance from center OO to chord ABAB.
In isosceles triangle OABOAB with OA=OB=6OA = OB = 6 and central angle AOB=120\angle AOB = 120^\circ, the perpendicular bisector from OO to ABAB meets ABAB at midpoint MM. AOM=60\angle AOM = 60^\circ, so OM=OAcos(60)=6×12=3OM = OA \cos(60^\circ) = 6 \times \frac{1}{2} = 3.
Determining OMOM allows us to find the sagitta (height) of the minor segment bounded by chord ABAB and minor arc ABAB.
2
Calculate the height of the minor segment (diameter of circle CC).
The height of the minor segment along the radius passing through MM to arc midpoint NN is MN=ONOM=63=3MN = ON - OM = 6 - 3 = 3. Since circle CC is tangent to ABAB at MM and to the arc at NN, segment MNMN is a diameter of circle CC, giving a diameter of 33.
The space between the chord midpoint and arc midpoint bounds circle CC, defining its diameter.
3
Find the radius of circle CC.
Radius rC=diameter2=32r_C = \frac{\text{diameter}}{2} = \frac{3}{2}.
The radius of circle CC is needed to calculate its sector area.
4
Compute the area of the 9090^\circ sector of circle CC.
\text{Area} = \frac{\theta}{360^\circ} \pi r_C^2 = \frac{90^\circ}{360^\circ} \pi \left(\frac{3}{2}\right)^2 = \frac{1}{4} \pi \left(\frac{9}{4}\right) = \frac{9\pi}{16}.
Multiply the fraction of the full circle represented by the central angle by the total area of circle CC.

Key Concept

Calculating sector area of an inscribed circle within a circle segment
Estimated Time:2m 0s
Question 54Question

In a circle centered at point OO with a radius of 66 units, points PP and QQ lie on the circle such that central angle POQ\angle POQ measures 120120^\circ. Which of the following statements are true? Select all such statements.

Select all that apply

Show answer & explanation

Answer: The length of minor arc PQPQ is 4π4\pi.; The area of minor sector POQPOQ is 12π12\pi.; The length of chord PQPQ is 636\sqrt{3}.

Answer

The true statements are that the length of minor arc PQPQ is 4π4\pi, the area of minor sector POQPOQ is 12π12\pi, and the length of chord PQPQ is 636\sqrt{3}.
The arc length of a 120120^\circ central angle is 13\frac{1}{3} of the total circumference 12π12\pi, which gives 4π4\pi. The sector area is 13\frac{1}{3} of the total area 36π36\pi, which gives 12π12\pi. Furthermore, by geometry of an isosceles triangle with vertex angle 120120^\circ and congruent sides 66, the base chord length is 2×6sin(60)=632 \times 6 \sin(60^\circ) = 6\sqrt{3}.

Step-by-Step Solution

1
Calculate the arc length of minor arc PQPQ
Arc length = 4π4\pi
Arc length equals θ360×2πr=120360×2π(6)=4π\frac{\theta}{360^\circ} \times 2\pi r = \frac{120^\circ}{360^\circ} \times 2\pi(6) = 4\pi.
2
Calculate the area of sector POQPOQ
Sector area = 12π12\pi
Sector area equals θ360×πr2=120360×π(62)=12π\frac{\theta}{360^\circ} \times \pi r^2 = \frac{120^\circ}{360^\circ} \times \pi(6^2) = 12\pi.
3
Determine the perimeter of sector POQPOQ
Perimeter = 4π+124\pi + 12
The boundary of a sector consists of the curved arc length plus two straight radii: 4π+6+6=4π+124\pi + 6 + 6 = 4\pi + 12.
4
Calculate the length of chord PQPQ
Chord PQ=63PQ = 6\sqrt{3}
Using triangle OPQOPQ with sides OP=OQ=6OP = OQ = 6 and POQ=120\angle POQ = 120^\circ, law of cosines or bisecting POQ\angle POQ into two 3030^\circ-6060^\circ-9090^\circ triangles yields chord length 2×(6sin60)=2×33=632 \times (6 \sin 60^\circ) = 2 \times 3\sqrt{3} = 6\sqrt{3}.

Key Concept

Arc Length, Sector Area, and Chord Relationships in Circles
Estimated Time:1m 30s
Question 55Question

A solid rectangular box has a length of 66 centimeters, a width of 44 centimeters, and a height of 55 centimeters. What is the total surface area, in square centimeters, of the box?

Show answer & explanation

Answer: 148148

Answer

The total surface area of the rectangular box is 148148 square centimeters.
The total surface area of a rectangular solid with length ll, width ww, and height hh is given by 2(lw+lh+wh)2(lw + lh + wh). Substituting l=6l = 6, w=4w = 4, and h=5h = 5 yields 2(64+65+45)=2(24+30+20)=2(74)=1482(6 \cdot 4 + 6 \cdot 5 + 4 \cdot 5) = 2(24 + 30 + 20) = 2(74) = 148 square centimeters.

Step-by-Step Solution

1
Identify the given dimensions of the rectangular box.
Length l=6l = 6 cm, width w=4w = 4 cm, and height h=5h = 5 cm.
These dimensions are required to compute the area of each face.
2
Calculate the surface area of the three distinct face pairs.
Top and bottom faces: 6×4=246 \times 4 = 24; Front and back faces: 6×5=306 \times 5 = 30; Left and right side faces: 4×5=204 \times 5 = 20.
A rectangular solid has six rectangular faces grouped into three identical pairs.
3
Apply the surface area formula A=2(lw+lh+wh)A = 2(lw + lh + wh).
A=2(24+30+20)=2(74)=148A = 2(24 + 30 + 20) = 2(74) = 148 square centimeters.
Summing the area of all six faces gives the total surface area.

Key Concept

Surface Area of a Rectangular Solid
Question 56Question

In a circle with center OO and radius 1212, radii OAOA and OBOB are perpendicular. Point CC lies on segment OAOA such that CC is the midpoint of OAOA. A line segment perpendicular to OAOA is drawn from point CC to intersect minor arc ABAB at point DD. What is the area of the region bounded by line segment CDCD, line segment CACA, and minor arc ADAD?

Show answer & explanation

Answer: 24π18324\pi - 18\sqrt{3}

Answer

24π18324\pi - 18\sqrt{3}
The area of the region bounded by line segment CDCD, segment CACA, and minor arc ADAD is obtained by subtracting the area of right triangle OCDOCD from the area of sector OADOAD. With OC=6OC = 6 and radius OD=12OD = 12, triangle OCDOCD is a 30609030^\circ-60^\circ-90^\circ right triangle, giving CD=63CD = 6\sqrt{3} and central angle AOD=60\angle AOD = 60^\circ. The sector area is 60360π(122)=24π\frac{60^\circ}{360^\circ} \cdot \pi (12^2) = 24\pi, and the triangle area is 12663=183\frac{1}{2} \cdot 6 \cdot 6\sqrt{3} = 18\sqrt{3}. Subtracting the triangle area from the sector area yields 24π18324\pi - 18\sqrt{3}.

Step-by-Step Solution

1
Determine the length of OCOC and the height CDCD
OC=6OC = 6 and CD=63CD = 6\sqrt{3}
Since CC is the midpoint of radius OA=12OA = 12, OC=6OC = 6. Triangle OCDOCD is a right triangle at CC with hypotenuse OD=12OD = 12 (radius of circle). By the Pythagorean theorem, CD=12262=108=63CD = \sqrt{12^2 - 6^2} = \sqrt{108} = 6\sqrt{3}.
2
Find the central angle AOD\angle AOD
AOD=60\angle AOD = 60^\circ
In right triangle OCDOCD, cos(AOD)=OCOD=612=12\cos(\angle AOD) = \frac{OC}{OD} = \frac{6}{12} = \frac{1}{2}, which implies AOD=60\angle AOD = 60^\circ.
3
Calculate the area of sector OADOAD
Area(Sector OAD)=24π\text{Area(Sector } OAD) = 24\pi$
The area of a sector with central angle 6060^\circ and radius 1212 is 60360π(122)=16144π=24π\frac{60^\circ}{360^\circ} \cdot \pi (12^2) = \frac{1}{6} \cdot 144\pi = 24\pi.
4
Calculate the area of right triangle OCDOCD
Area(Triangle OCD)=183\text{Area(Triangle } OCD) = 18\sqrt{3}
The area of right triangle OCDOCD is 12baseheight=12663=183\frac{1}{2} \cdot \text{base} \cdot \text{height} = \frac{1}{2} \cdot 6 \cdot 6\sqrt{3} = 18\sqrt{3}.
5
Subtract the area of triangle OCDOCD from the area of sector OADOAD
Area of shaded region=24π183\text{Area of shaded region} = 24\pi - 18\sqrt{3}
The bounded region is formed by removing triangle OCDOCD from sector OADOAD.

Key Concept

Calculating the area of a region bounded by a circle arc and line segments by subtracting a right triangle area from a sector area.
Question 57Question

In a plane, lines l1l_1 and l2l_2 are parallel (l1l2l_1 \parallel l_2). A transversal line tt intersects l1l_1 at point PP and l2l_2 at point QQ. The measures of two consecutive interior angles on the same side of transversal tt are (4x10)(4x - 10)^\circ on line l1l_1 and (3x+50)(3x + 50)^\circ on line l2l_2. A third line l3l_3 passes through point PP and is perpendicular to line l2l_2.

Which of the following statements MUST be true? Select all that apply.

Select all that apply

Show answer & explanation

Answer: x=20x = 20; The acute angle formed between line tt and line l3l_3 at point PP measures 2020^\circ.; The sum of all four interior angles located between lines l1l_1 and l2l_2 along transversal line tt is 360360^\circ.

Answer

The correct statements are that x=20x = 20, the acute angle formed between line tt and line l3l_3 at point PP measures 2020^\circ, and the sum of all four interior angles located between lines l1l_1 and l2l_2 along transversal line tt is 360360^\circ.
The statements confirming x=20x = 20, the 2020^\circ acute angle between lines tt and l3l_3, and the 360360^\circ interior angle sum are all correct because consecutive interior angles sum to 180180^\circ, perpendicular lines create 9090^\circ angles, and the four interior angles sum to 360360^\circ.

Step-by-Step Solution

1
Set up an equation for consecutive interior angles.
(4x10)+(3x+50)=180(4x - 10) + (3x + 50) = 180^\circ
Consecutive interior angles on the same side of a transversal intersecting parallel lines are supplementary.
2
Solve the algebraic equation for xx.
7x+40=180    7x=140    x=207x + 40 = 180 \implies 7x = 140 \implies x = 20
Combine like terms and isolate xx.
3
Calculate the interior angle measures at points PP and QQ.
Angle at P=4(20)10=70P = 4(20) - 10 = 70^\circ; Angle at Q=3(20)+50=110Q = 3(20) + 50 = 110^\circ
Substitute x=20x = 20 back into the original expressions.
4
Determine perpendicular relationships and angle measure between line tt and line l3l_3.
Angle between tt and l3l_3 at PP is 9070=2090^\circ - 70^\circ = 20^\circ
Line l3l2l_3 \perp l_2 implies l3l1l_3 \perp l_1 because l1l2l_1 \parallel l_2. Thus l3l_3 forms a 9090^\circ angle with l1l_1 at PP.
5
Sum the four interior angles between lines l1l_1 and l2l_2.
70+110+70+110=36070^\circ + 110^\circ + 70^\circ + 110^\circ = 360^\circ
The four interior angles comprise two pairs of interior angles measuring 7070^\circ and 110110^\circ each.

Key Concept

Parallel line angle theorems (consecutive interior angles, alternate interior angles) and perpendicular line relationships.
Question 58Question

An isosceles triangle has a base of length 1010 inches and a perimeter of 3636 inches. What is the area of the triangle, in square inches?

Show answer & explanation

Answer: 6060

Answer

6060 square inches
Subtracting the base length of 1010 inches from the total perimeter of 3636 inches leaves 2626 inches for the remaining two congruent sides, giving 1313 inches each. The perpendicular height divides the isosceles triangle into two right triangles with base 55 inches and hypotenuse 1313 inches. By the Pythagorean theorem, the height is 13252=12\sqrt{13^2 - 5^2} = 12 inches. Substituting base 1010 and height 1212 into the area formula 12×base×height\frac{1}{2} \times \text{base} \times \text{height} gives 12×10×12=60\frac{1}{2} \times 10 \times 12 = 60 square inches.

Step-by-Step Solution

1
Determine the length of the two congruent sides of the isosceles triangle.
Each side has a length of 1313 inches.
Since the perimeter is 3636 inches and the base is 1010 inches, the sum of the two equal sides is 3610=2636 - 10 = 26 inches. Dividing by 22 yields 1313 inches per side.
2
Calculate the perpendicular height of the triangle using the Pythagorean theorem.
The height of the triangle is 1212 inches.
Dropping an altitude from the top vertex to the base bisects the base into two segments of 55 inches. This creates two right triangles with a base of 55 inches and hypotenuse of 1313 inches. Thus, h=13252=16925=144=12h = \sqrt{13^2 - 5^2} = \sqrt{169 - 25} = \sqrt{144} = 12 inches.
3
Calculate the area of the isosceles triangle.
The area is 6060 square inches.
Using the triangle area formula Area=12×base×height\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}, we compute 12×10×12=60\frac{1}{2} \times 10 \times 12 = 60.

Key Concept

Properties of Isosceles Triangles and Area Formula
Question 59Question

A solid right circular cone has a base radius of rr and a height of h=43rh = \frac{4}{3}r. A solid sphere has a radius of RR. If the total surface area of the cone is equal to the total surface area of the sphere, which of the following statements must be true? Select all that apply.

Select all that apply

Show answer & explanation

Answer: The base radius of the cone, rr, is strictly greater than the radius of the sphere, RR.; The volume of the cone is strictly less than the volume of the sphere.; The ratio of the volume of the cone to the volume of the sphere is 64\frac{\sqrt{6}}{4}.

Answer

The statements confirming that the base radius of the cone is strictly greater than the radius of the sphere, that the volume of the cone is strictly less than the volume of the sphere, and that the ratio of the volume of the cone to the volume of the sphere is 64\frac{\sqrt{6}}{4} are all correct.
Equating the total surface area of the cone 83πr2\frac{8}{3}\pi r^2 with the surface area of the sphere 4πR24\pi R^2 yields r2R2=32\frac{r^2}{R^2} = \frac{3}{2}, which simplifies to rR=32\frac{r}{R} = \sqrt{\frac{3}{2}}. Because 1.5>1\sqrt{1.5} > 1, the base radius of the cone is strictly greater than the radius of the sphere. Furthermore, evaluating the ratio of their volumes gives VconeVsphere=49πr343πR3=13(rR)3=640.612\frac{V_{\text{cone}}}{V_{\text{sphere}}} = \frac{\frac{4}{9}\pi r^3}{\frac{4}{3}\pi R^3} = \frac{1}{3}\left(\frac{r}{R}\right)^3 = \frac{\sqrt{6}}{4} \approx 0.612. Because this ratio is strictly less than 11, the volume of the cone is strictly less than the volume of the sphere. Thus, the three true statements are those stating r>Rr > R, that the volume of the cone is strictly less than the sphere's volume, and that their volume ratio is 64\frac{\sqrt{6}}{4}.

Step-by-Step Solution

1
Calculate the slant height and total surface area of the cone in terms of rr.
Slant height l=r2+(43r)2=259r2=53rl = \sqrt{r^2 + \left(\frac{4}{3}r\right)^2} = \sqrt{\frac{25}{9}r^2} = \frac{5}{3}r. Total surface area Acone=πr2+πrl=πr2+πr(53r)=83πr2A_{\text{cone}} = \pi r^2 + \pi r l = \pi r^2 + \pi r\left(\frac{5}{3}r\right) = \frac{8}{3}\pi r^2.
The total surface area of a right circular cone is the sum of its base area πr2\pi r^2 and lateral area πrl\pi r l.
2
Equate the total surface area of the cone to the total surface area of the sphere to find the ratio rR\frac{r}{R}.
\frac{8}{3}\pi r^2 = 4\pi R^2 \implies 2 r^2 = 3 R^2 \implies \frac{r^2}{R^2} = \frac{3}{2} \implies \frac{r}{R} = \sqrt{\frac{3}{2}} = \frac{\sqrt{6}}{2}.
The surface area of a sphere of radius RR is 4πR24\pi R^2.
3
Compare the linear dimensions rr and RR.
Since rR=1.51.225>1\frac{r}{R} = \sqrt{1.5} \approx 1.225 > 1, it follows that r>Rr > R.
A ratio greater than 11 implies the numerator is larger than the denominator.
4
Express the volumes of both solids and compute their ratio VconeVsphere\frac{V_{\text{cone}}}{V_{\text{sphere}}}.
Vcone=13πr2h=13πr2(43r)=49πr3V_{\text{cone}} = \frac{1}{3}\pi r^2 h = \frac{1}{3}\pi r^2 \left(\frac{4}{3}r\right) = \frac{4}{9}\pi r^3. Vsphere=43πR3V_{\text{sphere}} = \frac{4}{3}\pi R^3. Therefore, VconeVsphere=49πr343πR3=13(rR)3=13(32)3/2=133322=64\frac{V_{\text{cone}}}{V_{\text{sphere}}} = \frac{\frac{4}{9}\pi r^3}{\frac{4}{3}\pi R^3} = \frac{1}{3}\left(\frac{r}{R}\right)^3 = \frac{1}{3}\left(\frac{3}{2}\right)^{3/2} = \frac{1}{3} \cdot \frac{3\sqrt{3}}{2\sqrt{2}} = \frac{\sqrt{6}}{4}.
Using standard volume formulas for cones and spheres and substituting the known linear dimension ratio.
5
Determine whether the cone's volume is greater than or less than the sphere's volume.
Since 640.612<1\frac{\sqrt{6}}{4} \approx 0.612 < 1, Vcone<VsphereV_{\text{cone}} < V_{\text{sphere}}.
A volume ratio less than 11 proves the cone has a smaller volume than the sphere.

Key Concept

Analyzing geometric scaling, volume, and total surface area relations between cones and spheres using variable constraints.
Question 60Question

In the xyxy-plane, line ll passes through the points (2,5)(2, 5) and (6,13)(6, 13). What is the slope of line ll?

Show answer & explanation

Answer: 2

Answer

The slope of line ll is 2.
The slope of a line passing through (x1,y1)(x_1, y_1) and (x2,y2)(x_2, y_2) is given by m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1}. Substituting (2,5)(2, 5) and (6,13)(6, 13) into the formula gives m=13562=84=2m = \frac{13 - 5}{6 - 2} = \frac{8}{4} = 2.

Step-by-Step Solution

1
Identify the coordinates of the two given points on line ll.
The points are (x1,y1)=(2,5)(x_1, y_1) = (2, 5) and (x2,y2)=(6,13)(x_2, y_2) = (6, 13).
Two points are required to calculate the slope of a straight line.
2
Apply the slope formula m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1}.
m=13562=84=2m = \frac{13 - 5}{6 - 2} = \frac{8}{4} = 2.
The slope measures the vertical change (rise) divided by the horizontal change (run).

Key Concept

Slope of a line through two points
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