Geometry and Trigonometry

178 soru

Soru 41Soru

If sin(θ)=53\sin(\theta) = \frac{\sqrt{5}}{3} and θ\theta is an acute angle, what is the value of tan2(θ)\tan^2(\theta)?

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Cevap: 1.25

Cevap

The correct answer is 1.25 (or the equivalent fraction 5/4).
Using the Pythagorean identity sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1, we find cos2(θ)=159=49\cos^2(\theta) = 1 - \frac{5}{9} = \frac{4}{9}. Since tan(θ)=sin(θ)cos(θ)\tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)}, it follows that tan2(θ)=sin2(θ)cos2(θ)=5/94/9=1.25\tan^2(\theta) = \frac{\sin^2(\theta)}{\cos^2(\theta)} = \frac{5/9}{4/9} = 1.25.

Adım Adım Çözüm

1
Calculate the square of the cosine of the angle using the Pythagorean identity.
cos2(θ)=1sin2(θ)=1(53)2=159=49\cos^2(\theta) = 1 - \sin^2(\theta) = 1 - \left(\frac{\sqrt{5}}{3}\right)^2 = 1 - \frac{5}{9} = \frac{4}{9}
The Pythagorean identity states that sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1 for any angle θ\theta.
2
Express the tangent squared in terms of sine squared and cosine squared.
tan2(θ)=sin2(θ)cos2(θ)\tan^2(\theta) = \frac{\sin^2(\theta)}{\cos^2(\theta)}
By definition, the tangent function is the ratio of sine to cosine, so tan(θ)=sin(θ)cos(θ)\tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)}.
3
Substitute the values of sin2(θ)\sin^2(\theta) and cos2(θ)\cos^2(\theta) to solve for tan2(θ)\tan^2(\theta).
tan2(θ)=5/94/9=54=1.25\tan^2(\theta) = \frac{5/9}{4/9} = \frac{5}{4} = 1.25
Plugging in the squared ratios and simplifying gives the final evaluation.

Anahtar Kavram

Pythagorean trigonometric identity and quotient identity of tangent
Soru 42Soru

A solid right circular cone has a base radius of rr and a height of hh. A right circular cylinder has a base radius that is twice the base radius of the cone, and a height that is three times the height of the cone. What is the ratio of the volume of the cone to the volume of the cylinder?

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Cevap: 136\frac{1}{36}

Cevap

The ratio of the volume of the cone to the volume of the cylinder is 136\frac{1}{36}
The volume of a right circular cone is given by Vcone=13πr2hV_{\text{cone}} = \frac{1}{3}\pi r^2 h. Since the cylinder has a radius that is twice that of the cone (2r2r) and a height that is three times that of the cone (3h3h), its volume is Vcylinder=π(2r)2(3h)=12πr2hV_{\text{cylinder}} = \pi (2r)^2(3h) = 12\pi r^2 h. Dividing the cone's volume by the cylinder's volume gives 13πr2h12πr2h=136\frac{\frac{1}{3}\pi r^2 h}{12\pi r^2 h} = \frac{1}{36}.

Adım Adım Çözüm

1
Write the formula for the volume of the cone.
Vcone=13πr2hV_{\text{cone}} = \frac{1}{3}\pi r^2 h
This establishes the volume of the first solid in terms of rr and hh.
2
Write the formula for the volume of the cylinder using the scaled dimensions.
Vcylinder=π(2r)2(3h)=12πr2hV_{\text{cylinder}} = \pi (2r)^2(3h) = 12\pi r^2 h
The cylinder has a radius of 2r2r and a height of 3h3h, and the volume formula is πR2H\pi R^2 H.
3
Calculate the ratio of the volume of the cone to the volume of the cylinder.
VconeVcylinder=13πr2h12πr2h=136\frac{V_{\text{cone}}}{V_{\text{cylinder}}} = \frac{\frac{1}{3}\pi r^2 h}{12\pi r^2 h} = \frac{1}{36}
This compares the two volumes directly by dividing the cone's volume by the cylinder's volume.

Anahtar Kavram

Volume of cylinders and cones and dimensional scaling relationships.

Alternatif Yöntem

Choose convenient sample values for the variables, such as r=1r = 1 and h=3h = 3. The volume of the cone is Vcone=13π(1)2(3)=πV_{\text{cone}} = \frac{1}{3}\pi (1)^2 (3) = \pi. The cylinder has radius 2(1)=22(1) = 2 and height 3(3)=93(3) = 9, so its volume is Vcylinder=π(2)2(9)=36πV_{\text{cylinder}} = \pi (2)^2 (9) = 36\pi. The ratio of the cone's volume to the cylinder's volume is π36π=136\frac{\pi}{36\pi} = \frac{1}{36}.
Tahmini Süre:1m 15s
Soru 43Soru

A solid metal sphere with radius rr is melted down and recast into a right circular cylinder with height 34r\frac{3}{4}r. If the total surface area of the cylinder is kπr2k\pi r^2, what is the value of kk?

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Cevap: 509\frac{50}{9}

Cevap

509\frac{50}{9}
The volume of the sphere with radius rr is V=43πr3V = \frac{4}{3}\pi r^3. When it is melted and recast into a right circular cylinder with radius RR and height h=34rh = \frac{3}{4}r, the volume remains the same. The volume of the cylinder is V=πR2hV = \pi R^2 h. Equating the two volumes gives 43πr3=πR2(34r)\frac{4}{3}\pi r^3 = \pi R^2 \left(\frac{3}{4}r\right). Dividing both sides by πr\pi r yields 43r2=34R2\frac{4}{3} r^2 = \frac{3}{4} R^2, which simplifies to R2=169r2R^2 = \frac{16}{9} r^2. Taking the square root of both sides gives R=43rR = \frac{4}{3}r. The total surface area of the cylinder is given by the formula S=2πR2+2πRhS = 2\pi R^2 + 2\pi R h. Substituting the values of RR and hh in terms of rr yields S=2π(43r)2+2π(43r)(34r)=2π(169r2)+2πr2=329πr2+189πr2=509πr2S = 2\pi \left(\frac{4}{3}r\right)^2 + 2\pi \left(\frac{4}{3}r\right)\left(\frac{3}{4}r\right) = 2\pi \left(\frac{16}{9}r^2\right) + 2\pi r^2 = \frac{32}{9}\pi r^2 + \frac{18}{9}\pi r^2 = \frac{50}{9}\pi r^2. Since the surface area is kπr2k\pi r^2, the value of kk is 509\frac{50}{9}.

Adım Adım Çözüm

1
Express the volume of the sphere in terms of its radius rr.
Vsphere=43πr3V_{\text{sphere}} = \frac{4}{3}\pi r^3
This is the standard formula for the volume of a sphere.
2
Equate the volume of the sphere to the volume of the cylinder to find the cylinder's radius RR in terms of rr.
43πr3=πR2(34r)    R2=169r2    R=43r\frac{4}{3}\pi r^3 = \pi R^2 \left(\frac{3}{4}r\right) \implies R^2 = \frac{16}{9}r^2 \implies R = \frac{4}{3}r
The volume of a cylinder is Vcylinder=πR2hV_{\text{cylinder}} = \pi R^2 h. Since the sphere is melted and recast into the cylinder, their volumes must be equal. Solving for R2R^2 and taking the square root gives the radius RR.
3
Use the total surface area formula for the cylinder to express the surface area in terms of rr.
A=2πR2+2πRh=2π(169r2)+2π(43r)(34r)=329πr2+2πr2=509πr2A = 2\pi R^2 + 2\pi R h = 2\pi\left(\frac{16}{9}r^2\right) + 2\pi\left(\frac{4}{3}r\right)\left(\frac{3}{4}r\right) = \frac{32}{9}\pi r^2 + 2\pi r^2 = \frac{50}{9}\pi r^2
The total surface area of a right circular cylinder consists of the area of the two circular bases and the lateral surface area.
4
Compare the calculated surface area to the given expression kπr2k\pi r^2 to find the value of kk.
k=509k = \frac{50}{9}
Equating 509πr2\frac{50}{9}\pi r^2 and kπr2k\pi r^2 yields the constant value kk.

Anahtar Kavram

Equating volumes of solids and calculating total surface area of a cylinder
Tahmini Süre:2m 30s
Soru 44Soru

In right triangle JKLJKL, the measure of angle KK is 9090^\circ. If cos(J)=0.28\cos(J) = 0.28, what is the value of sin(L)\sin(L)?

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Cevap: 0.28

Cevap

The correct answer is 0.28 (or the equivalent fraction 7/25).
In a right triangle, the two acute angles are complementary, meaning they add up to 9090^\circ. The co-function identity states that the sine of an acute angle is equal to the cosine of its complement. Therefore, in right triangle JKLJKL with right angle KK, sin(L)=cos(J)\sin(L) = \cos(J). Given that cos(J)=0.28\cos(J) = 0.28, the value of sin(L)\sin(L) must also be 0.280.28.

Adım Adım Çözüm

1
Determine the relationship between angles JJ and LL.
J+L=90J + L = 90^\circ
Since the sum of angles in a triangle is 180180^\circ and angle KK is 9090^\circ, the sum of the remaining two angles must be 18090=90180^\circ - 90^\circ = 90^\circ.
2
Use the co-function trigonometric identity.
sin(L)=cos(J)\sin(L) = \cos(J)
The sine of an acute angle in a right triangle is equal to the cosine of its complementary angle.
3
Substitute the given value of cos(J)\cos(J) into the identity.
sin(L)=0.28\sin(L) = 0.28
We are given that cos(J)=0.28\cos(J) = 0.28.

Anahtar Kavram

Complementary angle trigonometric identity (co-function identity)
Soru 45Soru

A rectangular box has a square base with side length xx inches and a height of 55 inches. The total surface area of the box is 192192 square inches. What is the value of xx?

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Cevap: 6

Cevap

The value of xx is 66.
The total surface area is found by adding the areas of all six faces. The top and bottom faces are squares with side length xx, so their combined area is 2x22x^2. The four vertical sides are rectangles with dimensions xx by 55, so their combined area is 4(5x)=20x4(5x) = 20x. Setting their sum equal to the total surface area gives 2x2+20x=1922x^2 + 20x = 192. Dividing by 22 yields x2+10x96=0x^2 + 10x - 96 = 0, which factors as (x+16)(x6)=0(x + 16)(x - 6) = 0. Since xx must be positive, x=6x = 6.

Adım Adım Çözüm

1
Set up the equation for the total surface area of the rectangular box.
Total Surface Area=2x2+20x=192\text{Total Surface Area} = 2x^2 + 20x = 192
The total surface area of a rectangular box with a square base of side length xx and height hh consists of two square bases (top and bottom) of area x2x^2 each, and four rectangular sides of area xhxh each. Substituting h=5h = 5 gives 2x2+4(5x)=2x2+20x2x^2 + 4(5x) = 2x^2 + 20x.
2
Simplify and set the quadratic equation to zero.
x2+10x96=0x^2 + 10x - 96 = 0
Dividing all terms by 22 simplifies the equation to x2+10x=96x^2 + 10x = 96. Subtracting 9696 from both sides sets the quadratic equation to standard form ax2+bx+c=0ax^2 + bx + c = 0.
3
Factor the quadratic equation and solve for the positive value of xx.
x=6x = 6
Factoring the equation gives (x+16)(x6)=0(x + 16)(x - 6) = 0, which yields solutions of x=16x = -16 and x=6x = 6. Since the side length of a geometric solid must be positive, we reject the negative solution.

Anahtar Kavram

Calculating the surface area of a rectangular prism and solving the resulting quadratic relationship.
Tahmini Süre:1m 35s
Soru 46Soru

In the triangles PQRPQR and STUSTU shown, PS\angle P \cong \angle S and QT\angle Q \cong \angle T. If the length of PQPQ is 1010, the length of QRQR is 1515, and the length of STST is 66, what is the length of TUTU?

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Cevap: 9

Cevap

9
Since two angles of triangle PQRPQR are congruent to two angles of triangle STUSTU, the triangles are similar by the Angle-Angle similarity theorem. Therefore, the ratio of corresponding side lengths is constant, which gives the equation PQST=QRTU\frac{PQ}{ST} = \frac{QR}{TU}. Substituting the given values yields 106=15TU\frac{10}{6} = \frac{15}{TU}. Solving for TUTU gives 10×TU=9010 \times TU = 90, which simplifies to TU=9TU = 9.

Adım Adım Çözüm

1
Identify the relationship between the two triangles.
The triangles are similar (PQRSTU\triangle PQR \sim \triangle STU).
Since two angles of triangle PQRPQR are congruent to two angles of triangle STUSTU, the triangles are similar by the Angle-Angle (AA) similarity theorem.
2
Set up a proportion using corresponding side lengths.
PQST=QRTU\frac{PQ}{ST} = \frac{QR}{TU}
Corresponding sides of similar triangles are proportional.
3
Substitute the known values and solve for the unknown side length.
TU=9TU = 9
Substituting the values gives 106=15TU\frac{10}{6} = \frac{15}{TU}. Cross-multiplying yields 10×TU=9010 \times TU = 90, which simplifies to TU=9TU = 9.

Anahtar Kavram

Triangle Similarity (AA Postulate)

Alternatif Yöntem

Find the scale factor from triangle PQRPQR to triangle STUSTU, which is STPQ=610=0.6\frac{ST}{PQ} = \frac{6}{10} = 0.6. Then, multiply the corresponding side QRQR by this scale factor: 15×0.6=915 \times 0.6 = 9.
Tahmini Süre:45s
Soru 47Soru

In triangle XYZXYZ, point WW lies on side XYXY and point VV lies on side XZXZ such that line segment WVWV is parallel to side YZYZ. If XW=4XW = 4, WY=2WY = 2, and WV=6WV = 6, what is the length of side YZYZ?

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Cevap: 9

Cevap

9
Because segment WVWV is parallel to segment YZYZ, triangle XWVXWV is similar to triangle XYZXYZ by the Angle-Angle (AA) similarity theorem. The ratio of the corresponding side lengths is constant, which gives the proportion YZWV=XYXW\frac{YZ}{WV} = \frac{XY}{XW}. The length of side XYXY is XW+WY=4+2=6XW + WY = 4 + 2 = 6. Substituting the values into the proportion yields YZ6=64\frac{YZ}{6} = \frac{6}{4}. Solving for YZYZ gives YZ=9YZ = 9.

Adım Adım Çözüm

1
Calculate the length of side XYXY
XY=6XY = 6
The length of side XYXY is the sum of segment lengths XWXW and WYWY: XY=XW+WY=4+2=6XY = XW + WY = 4 + 2 = 6.
2
Determine that triangle XWVXWV is similar to triangle XYZXYZ
XWVXYZ\triangle XWV \sim \triangle XYZ
Because segment WVWV is parallel to segment YZYZ, corresponding angles XWV\angle XWV and XYZ\angle XYZ are congruent, and corresponding angles XVW\angle XVW and XZY\angle XZY are congruent. Since they also share X\angle X, the two triangles are similar by the Angle-Angle (AA) similarity criterion.
3
Set up a proportion and solve for YZYZ
YZ=9YZ = 9
Corresponding sides of similar triangles are proportional: YZWV=XYXW\frac{YZ}{WV} = \frac{XY}{XW}. Substituting the known values gives YZ6=64\frac{YZ}{6} = \frac{6}{4}. Multiplying both sides by 6 yields YZ=364=9YZ = \frac{36}{4} = 9.

Anahtar Kavram

Finding side lengths in similar triangles using the Angle-Angle similarity theorem when a line is parallel to one side of a triangle.
Soru 48Soru

Triangle ABCABC is similar to triangle DEFDEF, where vertex AA corresponds to vertex DD, vertex BB corresponds to vertex EE, and vertex CC corresponds to vertex FF. The length of side ABAB is 66, the length of side BCBC is 88, and the length of side DEDE is 33. What is the length of side EFEF?

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Cevap: 44

Cevap

The correct answer is 44.
The correct answer is 44. Since triangle ABCABC is similar to triangle DEFDEF, the ratio of their corresponding side lengths must be equal. We set up the proportion ABDE=BCEF\frac{AB}{DE} = \frac{BC}{EF}. Substituting the given values gives 63=8EF\frac{6}{3} = \frac{8}{EF}, which simplifies to 2=8EF2 = \frac{8}{EF}. Solving for EFEF gives EF=4EF = 4.

Adım Adım Çözüm

1
Identify corresponding sides of the two similar triangles.
Since triangle ABCABC is similar to triangle DEFDEF, side ABAB corresponds to side DEDE and side BCBC corresponds to side EFEF.
The ordering of vertices in similarity statements determines corresponding parts.
2
Set up a proportion using the ratios of corresponding sides.
The proportion is ABDE=BCEF\frac{AB}{DE} = \frac{BC}{EF}, which translates to 63=8EF\frac{6}{3} = \frac{8}{EF}.
Corresponding sides of similar triangles are proportional.
3
Solve for the unknown length EFEF.
2=8EF2 = \frac{8}{EF}, which gives EF=82=4EF = \frac{8}{2} = 4.
Isolate the variable by simplifying the ratio and solving the algebraic equation.

Anahtar Kavram

The ratio of corresponding side lengths in similar triangles is constant.
Soru 49Soru

A right circular cylinder has a height of hh and a base radius of rr. A sphere has a radius of 2r2r. If the volume of the sphere is 88 times the volume of the cylinder, what is the value of the ratio hr\frac{h}{r}?

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Cevap: 43\frac{4}{3}

Cevap

43\frac{4}{3}
The volume of a sphere with radius RR is 43πR3\frac{4}{3}\pi R^3. Substituting R=2rR = 2r gives a volume of 43π(2r)3=323πr3\frac{4}{3}\pi (2r)^3 = \frac{32}{3}\pi r^3. The volume of a cylinder is πr2h\pi r^2 h. Since the volume of the sphere is 88 times the volume of the cylinder, we can set up the equation 323πr3=8πr2h\frac{32}{3}\pi r^3 = 8\pi r^2 h. Dividing both sides of the equation by 8πr28\pi r^2 yields 43r=h\frac{4}{3}r = h, which means the ratio hr\frac{h}{r} is 43\frac{4}{3}.

Adım Adım Çözüm

1
Express the volume of both the cylinder and the sphere in terms of rr and hh.
The cylinder has volume Vcylinder=πr2hV_{\text{cylinder}} = \pi r^2 h. The sphere has radius 2r2r, so its volume is Vsphere=43π(2r)3=323πr3V_{\text{sphere}} = \frac{4}{3}\pi(2r)^3 = \frac{32}{3}\pi r^3.
This establishes formulas for both volumes using the given variables.
2
Set up the equation using the given relation that the volume of the sphere is 88 times the volume of the cylinder.
323πr3=8πr2h\frac{32}{3}\pi r^3 = 8\pi r^2 h
This represents the mathematical relationship specified in the problem statement.
3
Solve for the ratio hr\frac{h}{r} by dividing both sides of the equation by 8πr28\pi r^2.
323×8r=h    43r=h    hr=43\frac{32}{3 \times 8} r = h \implies \frac{4}{3}r = h \implies \frac{h}{r} = \frac{4}{3}
This isolates the ratio of the height to the radius to get the final result.

Anahtar Kavram

Using the formulas for the volume of a right circular cylinder and a sphere to solve for an unknown dimension ratio.
Soru 50Soru

Triangle LMNLMN is similar to triangle XYZXYZ, where vertex LL corresponds to vertex XX, vertex MM corresponds to vertex YY, and vertex NN corresponds to vertex ZZ. The length of side LMLM is 55, the length of side XYXY is 1515, and the length of side YZYZ is 2424. What is the length of side MNMN?

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Cevap: 8

Cevap

8
The correct answer is 8. Similar triangles have corresponding side lengths that are proportional. The ratio of the length of side LMLM to the length of its corresponding side XYXY is 55 to 1515, which simplifies to 11 to 33. Since side MNMN corresponds to side YZYZ, the ratio of the length of side MNMN to the length of side YZYZ must also be 11 to 33. Setting up the proportion 13=MN24\frac{1}{3} = \frac{MN}{24} and solving for the length of side MNMN yields 88.

Adım Adım Çözüm

1
Identify corresponding sides of the similar triangles and set up a proportion.
LMXY=MNYZ\frac{LM}{XY} = \frac{MN}{YZ}
Similar triangles have proportional corresponding side lengths.
2
Substitute the given values into the proportion.
515=MN24\frac{5}{15} = \frac{MN}{24}
The given lengths are LM=5LM = 5, XY=15XY = 15, and YZ=24YZ = 24.
3
Simplify the fraction and solve for MNMN.
MN=8MN = 8
515\frac{5}{15} simplifies to 13\frac{1}{3}. Multiplying both sides of 13=MN24\frac{1}{3} = \frac{MN}{24} by 2424 yields MN=8MN = 8.

Anahtar Kavram

Triangle Similarity and Proportional Side Lengths

Alternatif Yöntem

Find the scale factor from triangle LMNLMN to triangle XYZXYZ by dividing XYXY by LMLM: 15/5=315 / 5 = 3. Since triangle XYZXYZ is 33 times larger than triangle LMNLMN, divide the length of side YZYZ by 33 to find the length of corresponding side MNMN: 24/3=824 / 3 = 8.
Tahmini Süre:45s
Soru 51Soru

In similar triangles JKLJKL and WXYWXY, the ratio of the length of side JKJK to the length of its corresponding side WXWX is 11 to 44. If the length of side WXWX is x+9x + 9 and the length of side JKJK is xx, what is the value of xx?

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Cevap: 3

Cevap

The correct answer is 3.
Because triangles JKLJKL and WXYWXY are similar, the ratio of corresponding side lengths is constant. Since the ratio of JKJK to WXWX is 11 to 44, the relationship can be written as xx+9=14\frac{x}{x + 9} = \frac{1}{4}. Cross-multiplying yields 4x=x+94x = x + 9. Subtracting xx from both sides gives 3x=93x = 9, and dividing by 33 gives the final answer x=3x = 3.

Adım Adım Çözüm

1
Set up a proportion using the ratio of corresponding side lengths.
xx+9=14\frac{x}{x + 9} = \frac{1}{4}
The ratio of corresponding side lengths in similar triangles is constant.
2
Cross-multiply to eliminate fractions.
4x=x+94x = x + 9
Multiplying both sides by both denominators simplifies the equation.
3
Solve for the variable xx.
x=3x = 3
Subtracting xx from both sides gives 3x=93x = 9, and dividing by 33 gives x=3x = 3.

Anahtar Kavram

The corresponding side lengths of similar triangles are proportional.
Soru 52Soru

A solid right circular cylinder has a radius of rr centimeters and a height of 66 centimeters. A solid sphere has a radius of rr centimeters. If the sum of the volumes of the cylinder and the sphere is equal to the volume of a right circular cylinder with a radius of 2r2r centimeters and a height of 22 centimeters, what is the value of rr?

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Cevap: 1.5

Cevap

The correct answer is 1.5 (or 3/2).
The correct answer is 1.5. By using the formulas for the volume of a cylinder (V=πr2hV = \pi r^2 h) and a sphere (V=43πr3V = \frac{4}{3}\pi r^3), the total volume of the first cylinder and the sphere is 6πr2+43πr36\pi r^2 + \frac{4}{3}\pi r^3. The second cylinder has a volume of π(2r)2(2)=8πr2\pi(2r)^2(2) = 8\pi r^2. Setting them equal gives 6πr2+43πr3=8πr26\pi r^2 + \frac{4}{3}\pi r^3 = 8\pi r^2. Subtracting 6πr26\pi r^2 from both sides gives 43πr3=2πr2\frac{4}{3}\pi r^3 = 2\pi r^2. Dividing both sides by πr2\pi r^2 (since r>0r > 0) simplifies to 43r=2\frac{4}{3}r = 2, which solves to r=1.5r = 1.5.

Adım Adım Çözüm

1
Express the volume of the first cylinder using the formula V=πr2hV = \pi r^2 h.
V1=6πr2V_1 = 6\pi r^2
To represent the cylinder's volume in terms of its radius.
2
Express the volume of the sphere using the formula V=43πr3V = \frac{4}{3}\pi r^3.
V2=43πr3V_2 = \frac{4}{3}\pi r^3
To represent the sphere's volume in terms of its radius.
3
Express the volume of the second cylinder, which has a radius of 2r2r and a height of 22.
V3=π(2r)2(2)=8πr2V_3 = \pi (2r)^2(2) = 8\pi r^2
To represent the larger cylinder's volume in terms of rr.
4
Set up the equation where the sum of the first cylinder and sphere volumes equals the second cylinder volume.
6πr2+43πr3=8πr26\pi r^2 + \frac{4}{3}\pi r^3 = 8\pi r^2
To relate the volumes as given in the problem statement.
5
Simplify the equation by subtracting 6πr26\pi r^2 from both sides.
43πr3=2πr2\frac{4}{3}\pi r^3 = 2\pi r^2
To isolate the cubic term on one side.
6
Divide both sides of the equation by πr2\pi r^2 since r>0r > 0.
43r=2\frac{4}{3}r = 2
To reduce the polynomial equation to a linear equation.
7
Multiply both sides by 34\frac{3}{4} to solve for rr.
r=1.5r = 1.5
To find the final numerical value of the radius.

Anahtar Kavram

Volume of cylinders and spheres
Soru 53Soru

A rectangular prism has a length of 88 centimeters, a width of 66 centimeters, and a height of hh centimeters. A right circular cylinder has a base radius of 33 centimeters and a height of hh centimeters. If the volume of the rectangular prism is VV cubic centimeters and the volume of the cylinder is WW cubic centimeters, which of the following expressions represents the ratio of VV to WW ?

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Cevap: 163π\frac{16}{3\pi}

Cevap

The ratio of the volume of the rectangular prism to the volume of the cylinder is 163π\frac{16}{3\pi}.
The volume of the rectangular prism is the product of its dimensions: V=8×6×h=48hV = 8 \times 6 \times h = 48h. The volume of the right circular cylinder is calculated using the formula πr2h\pi r^2 h: W=π×32×h=9πhW = \pi \times 3^2 \times h = 9\pi h. The ratio of VV to WW is represented by the fraction VW=48h9πh\frac{V}{W} = \frac{48h}{9\pi h}. Simplifying the fraction by canceling the common variable hh and dividing the numerator and denominator by 33 yields the expression 163π\frac{16}{3\pi}.

Adım Adım Çözüm

1
Write the expression for the volume of the rectangular prism, VV, in terms of hh.
V=8×6×h=48hV = 8 \times 6 \times h = 48h
The volume of a rectangular prism is calculated using the formula Volume=lwh\text{Volume} = lwh, where ll is the length, ww is the width, and hh is the height.
2
Write the expression for the volume of the cylinder, WW, in terms of hh.
W=π×32×h=9πhW = \pi \times 3^2 \times h = 9\pi h
The volume of a right circular cylinder is calculated using the formula Volume=πr2h\text{Volume} = \pi r^2 h, where rr is the base radius and hh is the height.
3
Express the ratio of VV to WW as a fraction and simplify it.
VW=48h9πh=489π=163π\frac{V}{W} = \frac{48h}{9\pi h} = \frac{48}{9\pi} = \frac{16}{3\pi}
The ratio of VV to WW is given by VW\frac{V}{W}. The common height variable hh cancels out from both the numerator and the denominator, and the fraction 489\frac{48}{9} simplifies to 163\frac{16}{3} by dividing both numbers by their greatest common divisor, 33.

Anahtar Kavram

Calculating and comparing volumes of rectangular prisms and right circular cylinders in terms of algebraic variables.
Soru 54Soru

In the xyxy-plane, a square has vertices at (0,0)(0,0), (10,0)(10,0), (10,10)(10,10), and (0,10)(0,10). A line that passes through the points (0,2)(0,2) and (8,10)(8,10) divides the square into two regions. What is the area of the larger region?

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Cevap: 68

Cevap

The area of the larger region is 68.
The total area of the square is 102=10010^2 = 100. The line segment between (0,2)(0,2) on the left boundary and (8,10)(8,10) on the top boundary forms a right triangle with the top-left vertex of the square (0,10)(0,10). The legs of this right triangle have lengths 102=810 - 2 = 8 and 80=88 - 0 = 8, so its area is 12×8×8=32\frac{1}{2} \times 8 \times 8 = 32. The area of the other region is 10032=68100 - 32 = 68. The larger area is therefore 68.

Adım Adım Çözüm

1
Calculate the area of the square
100
The square has vertices at (0,0)(0,0), (10,0)(10,0), (10,10)(10,10), and (0,10)(0,10), which gives a side length of 10. The area of a square is side2\text{side}^2.
2
Determine the dimensions of the smaller triangular region formed by the line
Legs of length 8 and 8
The line intersects the left edge at (0,2)(0,2) and the top edge at (8,10)(8,10). The corner of the square is at (0,10)(0,10). The distance from (0,2)(0,2) to (0,10)(0,10) is 8, and the distance from (8,10)(8,10) to (0,10)(0,10) is 8.
3
Calculate the area of the smaller triangular region
32
The area of a right triangle is 12×base×height=12×8×8=32\frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 8 \times 8 = 32.
4
Subtract the area of the smaller region from the total area of the square to find the area of the larger region
68
The area of the larger region is the total area of the square minus the area of the smaller region: 10032=68100 - 32 = 68.

Anahtar Kavram

Calculating the area of a region by partitioning a geometric shape or using subtraction of areas.
Soru 55Soru

In right triangle ABCABC, the measure of angle BB is 9090^\circ. If the length of side ABAB is 6 and the length of side ACAC is 10, what is the length of side BCBC?

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Cevap: 8

Cevap

The length of side BCBC is 8.
By applying the Pythagorean theorem to right triangle ABCABC, we have AB2+BC2=AC2AB^2 + BC^2 = AC^2. Substituting the given values gives 62+BC2=1026^2 + BC^2 = 10^2, or 36+BC2=10036 + BC^2 = 100. Subtracting 36 from both sides gives BC2=64BC^2 = 64, and taking the square root yields BC=8BC = 8.

Adım Adım Çözüm

1
Identify the hypotenuse and the given leg in the right triangle.
The hypotenuse is AC=10AC = 10 and the given leg is AB=6AB = 6.
The side opposite the 9090^\circ angle (angle BB) is always the hypotenuse.
2
Apply the Pythagorean theorem.
AB2+BC2=AC2AB^2 + BC^2 = AC^2, which becomes 62+BC2=1026^2 + BC^2 = 10^2.
The Pythagorean theorem states that the sum of the squares of the legs of a right triangle equals the square of the hypotenuse.
3
Solve for the unknown leg BCBC.
36+BC2=100    BC2=64    BC=836 + BC^2 = 100 \implies BC^2 = 64 \implies BC = 8.
Simplify the squares, subtract 36 from both sides, and find the principal square root of 64.

Anahtar Kavram

The Pythagorean Theorem
Soru 56Soru

A right circular cylinder and a right circular cone have equal volumes. The radius of the cylinder's base is 33 times the radius of the cone's base. If the height of the cone is kk times the height of the cylinder, what is the value of kk?

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Cevap: 27

Cevap

27
The volume of a cylinder is Vcylinder=πrcylinder2hcylinderV_{\text{cylinder}} = \pi r_{\text{cylinder}}^2 h_{\text{cylinder}} and the volume of a cone is Vcone=13πrcone2hconeV_{\text{cone}} = \frac{1}{3} \pi r_{\text{cone}}^2 h_{\text{cone}}. Let the base radius of the cone be rr and the height of the cylinder be hh. According to the problem, the base radius of the cylinder is 3r3r and the height of the cone is khkh. Setting the volumes equal to each other gives π(3r)2h=13πr2(kh)\pi (3r)^2 h = \frac{1}{3} \pi r^2 (kh). Squaring the term in parentheses simplifies the equation to 9πr2h=k3πr2h9 \pi r^2 h = \frac{k}{3} \pi r^2 h. Dividing both sides by the common term πr2h\pi r^2 h yields 9=k39 = \frac{k}{3}. Multiplying both sides by 3 results in k=27k = 27.

Adım Adım Çözüm

1
State the standard volume formulas for a right circular cylinder and a right circular cone.
Vcylinder=πrcylinder2hcylinderV_{\text{cylinder}} = \pi r_{\text{cylinder}}^2 h_{\text{cylinder}} and Vcone=13πrcone2hconeV_{\text{cone}} = \frac{1}{3} \pi r_{\text{cone}}^2 h_{\text{cone}}
To establish the mathematical equations governing the volume of each solid.
2
Define variables for the cone's radius (rr) and the cylinder's height (hh), then write the cylinder's radius and the cone's height using the given relationships.
rcylinder=3rr_{\text{cylinder}} = 3r, rcone=rr_{\text{cone}} = r, hcylinder=hh_{\text{cylinder}} = h, and hcone=khh_{\text{cone}} = kh
To express all variables in terms of rr, hh, and the constant kk so they can be compared directly.
3
Substitute the expressions into the volume formulas and set the two volumes equal to each other.
π(3r)2h=13πr2(kh)\pi (3r)^2 h = \frac{1}{3} \pi r^2 (kh)
The problem states that the cylinder and the cone have equal volumes.
4
Simplify the equation by squaring the cylinder's radius and dividing both sides by the common factors.
9πr2h=k3πr2h    9=k3    k=279 \pi r^2 h = \frac{k}{3} \pi r^2 h \implies 9 = \frac{k}{3} \implies k = 27
To isolate and solve for the constant kk.

Anahtar Kavram

Relating the volumes of geometric solids through algebraic substitution and dimension scaling.
Soru 57Soru

A landscape architect is designing two similar gardens. The smaller garden is in the shape of a regular hexagon and has an area of 24324\sqrt{3} square meters. The larger garden is also a regular hexagon, and its perimeter is 33 times the perimeter of the smaller garden. An inscribed circular fountain is to be placed in the center of the larger garden, touching all six sides. What is the area, in square meters, of the circular fountain?

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Cevap: 108π108\pi

Cevap

The area of the circular fountain is 108π108\pi square meters.
The side length of the smaller hexagon is calculated to be 44 meters using the area formula for a regular hexagon. Because the larger hexagon's perimeter is scaled by a factor of 33, its side length is 1212 meters. The radius of the inscribed circle is the apothem of the larger hexagon, which is 12×32=6312 \times \frac{\sqrt{3}}{2} = 6\sqrt{3} meters. Squaring this radius and multiplying by π\pi results in an area of 108π108\pi square meters.

Adım Adım Çözüm

1
Find the side length of the smaller regular hexagon.
The side length is 44 meters.
The area of a regular hexagon with side length s1s_1 is given by A=332s12A = \frac{3\sqrt{3}}{2} s_1^2. Setting this equal to 24324\sqrt{3} yields s12=16s_1^2 = 16, so s1=4s_1 = 4.
2
Determine the side length of the larger regular hexagon.
The side length is 1212 meters.
Since the two hexagons are similar, the ratio of their perimeters is equal to the linear scale factor of their sides. The perimeter of the larger hexagon is 33 times that of the smaller hexagon, so its side length is s2=3×4=12s_2 = 3 \times 4 = 12.
3
Find the radius of the inscribed circle in the larger hexagon.
The radius is 636\sqrt{3} meters.
The radius rr of the inscribed circle is the apothem of the regular hexagon. For a hexagon with side length s2=12s_2 = 12, the apothem is r=s232=1232=63r = s_2 \frac{\sqrt{3}}{2} = 12 \frac{\sqrt{3}}{2} = 6\sqrt{3}.
4
Calculate the area of the inscribed circular fountain.
The area is 108π108\pi square meters.
Using the area formula for a circle, A=πr2A = \pi r^2, we substitute r=63r = 6\sqrt{3} to get A=π(63)2=108πA = \pi (6\sqrt{3})^2 = 108\pi.

Anahtar Kavram

Area of regular polygons, similarity ratio scaling, and properties of inscribed circles.
Soru 58Soru

A rectangular garden has a length of 1212 feet and a width of 55 feet. A gardener wants to place a straight wooden diagonal walk from one corner of the garden to the opposite corner. What is the length, in feet, of the diagonal walk?

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Cevap: 1313

Cevap

The length of the diagonal walk is 1313 feet.
The diagonal of the rectangular garden forms a right triangle with the garden's length and width acting as the legs. By applying the Pythagorean theorem, a2+b2=c2a^2 + b^2 = c^2, where a=5a = 5 and b=12b = 12, we get 52+122=25+144=1695^2 + 12^2 = 25 + 144 = 169. Taking the square root of 169169 gives 1313. Thus, the length of the diagonal walk is 1313 feet.

Adım Adım Çözüm

1
Identify the right triangle formed by the length, width, and diagonal of the rectangle.
A right triangle is formed where the two legs are the length (1212 feet) and the width (55 feet), and the hypotenuse is the diagonal walk (dd).
The corners of a rectangle form 9090^\circ angles, making the diagonal the hypotenuse of a right triangle.
2
Apply the Pythagorean theorem, a2+b2=c2a^2 + b^2 = c^2, where a=5a = 5, b=12b = 12, and c=dc = d.
52+122=d25^2 + 12^2 = d^2
To relate the legs of a right triangle to its hypotenuse.
3
Simplify the equation to solve for dd.
25+144=d225 + 144 = d^2, which simplifies to 169=d2169 = d^2. Taking the square root of both sides gives d=13d = 13.
To find the numerical value of the hypotenuse.

Anahtar Kavram

Right Triangles and the Pythagorean Theorem
Tahmini Süre:45s
Soru 59Soru

An acute angle θ\theta in a right triangle satisfies cos(θ)=35\cos(\theta) = \frac{3}{5}. If ϕ\phi is the other acute angle of the triangle, what is the value of sin(ϕ)tan(θ)\sin(\phi) \tan(\theta)?

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Cevap: 45\frac{4}{5}

Cevap

four-fifths
The correct answer is four-fifths. Because θ\theta and ϕ\phi are complementary angles in a right triangle, sin(ϕ)\sin(\phi) equals cos(θ)\cos(\theta), which is given as three-fifths. Using the Pythagorean identity, sin(θ)\sin(\theta) is four-fifths, making tan(θ)\tan(\theta) equal to four-thirds. Multiplying sin(ϕ)\sin(\phi) and tan(θ)\tan(\theta) gives three-fifths times four-thirds, which simplifies to four-fifths.

Adım Adım Çözüm

1
Use the complementary angle relationship to find sin(ϕ)\sin(\phi).
sin(ϕ)=cos(θ)=35\sin(\phi) = \cos(\theta) = \frac{3}{5}
The two acute angles in a right triangle, θ\theta and ϕ\phi, sum to 9090^\circ. Therefore, the sine of one angle equals the cosine of the other.
2
Find sin(θ)\sin(\theta) using the Pythagorean identity.
sin(θ)=45\sin(\theta) = \frac{4}{5}
Since sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1, we have sin2(θ)+(35)2=1\sin^2(\theta) + \left(\frac{3}{5}\right)^2 = 1, which gives sin2(θ)=1625\sin^2(\theta) = \frac{16}{25}. Because θ\theta is acute, sin(θ)=45\sin(\theta) = \frac{4}{5}.
3
Calculate tan(θ)\tan(\theta) using the quotient identity.
tan(θ)=43\tan(\theta) = \frac{4}{3}
By definition, tan(θ)=sin(θ)cos(θ)=4/53/5=43\tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)} = \frac{4/5}{3/5} = \frac{4}{3}.
4
Multiply sin(ϕ)\sin(\phi) by tan(θ)\tan(\theta).
sin(ϕ)tan(θ)=45\sin(\phi) \tan(\theta) = \frac{4}{5}
Substitute the found values: sin(ϕ)tan(θ)=35×43=45\sin(\phi) \tan(\theta) = \frac{3}{5} \times \frac{4}{3} = \frac{4}{5}.

Anahtar Kavram

Trigonometric co-function identities and quotient identities in right triangles
Soru 60Soru

A straight ladder is leaning against a vertical wall. The base of the ladder is placed 99 feet from the bottom of the wall. If the top of the ladder touches the wall at a height of 1212 feet above the ground, what is the length, in feet, of the ladder?

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Cevap: 15

Cevap

The length of the ladder is 1515 feet.
By representing the scenario as a right triangle, the two perpendicular sides (legs) have lengths of 99 feet and 1212 feet. Using the Pythagorean theorem (a2+b2=c2a^2 + b^2 = c^2), we find 92+122=81+144=2259^2 + 12^2 = 81 + 144 = 225. Taking the square root of 225225 gives the hypotenuse length, which is 1515 feet.

Adım Adım Çözüm

1
Model the scenario using a right triangle.
A right triangle where the vertical leg is 1212 feet (height on the wall), the horizontal leg is 99 feet (distance along the ground), and the hypotenuse is cc (the ladder length).
The intersection of the vertical wall and the horizontal ground forms a right angle (9090^\circ).
2
Set up the Pythagorean equation.
92+122=c29^2 + 12^2 = c^2
The Pythagorean theorem states that the sum of the squares of the legs of a right triangle equals the square of the hypotenuse.
3
Solve for the hypotenuse cc.
c=81+144=225=15c = \sqrt{81 + 144} = \sqrt{225} = 15
Simplifying the arithmetic yields 225225, and taking the square root gives the final length of 1515 feet.

Anahtar Kavram

Pythagorean Theorem
Tahmini Süre:45s
ÖncekiSayfa 3 / 9Sonraki
Geometry and Trigonometry Alıştırma Soruları — SAT — Sayfa 3 | Examkin