Quantitative Aptitude
Mensuration
2,507 Questions
Mensuration Questions
D
Correct answer
Explanation
Volume of a sphere is proportional to the cube of its radius. If the radius is doubled (2r), the volume becomes (2r)^3 = 8r^3. The ratio is 1:8.
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2 times
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4 times
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6 times
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8 times
D
Correct answer
Explanation
Volume of a cone V = (1/3) * pi * r^2 * h. If r becomes 2r and h becomes 2h, new volume V' = (1/3) * pi * (2r)^2 * (2h) = (1/3) * pi * 4r^2 * 2h = 8 * ((1/3) * pi * r^2 * h) = 8V.
B
Correct answer
Explanation
Surface area of sphere = 4 * pi * r^2. Volume = 4/3 * pi * r^3. Setting them equal: 4 * pi * r^2 = 4/3 * pi * r^3. 1 = 1/3 * r. r = 3.
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$\displaystyle 115.5cm^{2}$
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$\displaystyle 151.5cm^{2}$
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$\displaystyle 155cm^{2}$
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$\displaystyle 151cm^{2}$
A
Correct answer
Explanation
A sphere cut in half creates two hemispheres. Each hemisphere has a curved surface area (2 * pi * r^2) and a flat circular base (pi * r^2). Total surface area = 3 * pi * r^2. r = 3.5. Area = 3 * (22/7) * 3.5 * 3.5 = 3 * 22 * 0.5 * 3.5 = 115.5.
A
Correct answer
Explanation
Curved surface area (CSA) = 2 * pi * r * h = 264. Volume (V) = pi * r^2 * h = 924. Dividing V by CSA: (pi * r^2 * h) / (2 * pi * r * h) = 924 / 264. This simplifies to r / 2 = 3.5, so r = 7. Substitute r = 7 into CSA: 2 * (22/7) * 7 * h = 264, so 44 * h = 264, h = 6.
C
Correct answer
Explanation
Radius r = 5k, height h = 12k. Volume = (1/3) * pi * r^2 * h = 314. (1/3) * 3.14 * (25k^2) * (12k) = 314. 3.14 * 100k^3 = 314 => k^3 = 1 => k = 1. So r = 5, h = 12. Slant height l = sqrt(r^2 + h^2) = sqrt(25 + 144) = 13.
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1 : 2 : 3
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3 : 2 : 1
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2 : 1 : 3
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1 : 3 : 2
D
Correct answer
Explanation
Cone: (1/3) * pi * r^2 * h = (1/3) * pi * 1^2 * 1 = pi/3. Cylinder: pi * r^2 * h = pi * 1^2 * 1 = pi. Hemisphere: (2/3) * pi * r^3 = (2/3) * pi * 1^3 = 2pi/3. Ratio: pi/3 : pi : 2pi/3 = 1 : 3 : 2.
D
Correct answer
Explanation
The volume of a sphere is 4/3 pi r^3 and its surface area is 4 pi r^2. Equating their numerical values gives 4/3 pi r^3 = 4 pi r^2, so r = 3 m, with r = 0 excluded.
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$ \displaystyle (\sqrt{2}+1):3:4 $
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$ \displaystyle (\sqrt{3}+1):3:4 $
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$ \displaystyle \sqrt{2}:3:4 $
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$ \displaystyle \sqrt{3}:7:8 $
A
Correct answer
Explanation
With radius r as the common height, the cone's whole surface area is (sqrt(2) + 1)pi r^2. The hemisphere and cylinder have whole surface areas 3pi r^2 and 4pi r^2, respectively. Their ratio is therefore (sqrt(2) + 1) : 3 : 4.
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$ \displaystyle \frac{4}{3}\times (5\pi )cm^{3} $
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$ \displaystyle \frac{4}{3} \pi cm^{3} $
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$ \displaystyle 5\pi cm^{3} $
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$ \displaystyle \frac{10\pi }{3}cm^{3} $
B
Correct answer
Explanation
The greatest sphere that can be cut from a cylinder of radius 1 cm and height 5 cm is limited by the radius. The sphere's radius is 1 cm. Volume = (4/3) * pi * r^3 = (4/3) * pi * 1^3 = (4/3) * pi.
B
Correct answer
Explanation
Volume of cylinder = pi * r^2 * h = pi * (0.75)^2 * 1 = 0.5625 * pi. Volume of sphere = 4/3 * pi * R^3. 4/3 * R^3 = 0.5625. R^3 = 0.5625 * 3 / 4 = 0.421875. R = cube root(0.421875) = 0.75.
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$ \displaystyle 190 \pi cm^{2} $
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$ \displaystyle 192 \pi cm^{2} $
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$ \displaystyle 195 \pi cm^{2} $
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$ \displaystyle 198 \pi cm^{2} $
B
Correct answer
Explanation
Surface area = Cylinder lateral area + Base area + Cone lateral area. Cylinder lateral = 2 * pi * r * h = 2 * pi * 6 * 8 = 96 pi. Base = pi * r^2 = 36 pi. Cone lateral = pi * r * l, where l = sqrt(r^2 + h^2) = 10. Cone lateral = pi * 6 * 10 = 60 pi. Total = 96 pi + 36 pi + 60 pi = 192 pi.
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$ \displaystyle 2\pi r^{2} $
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$ \displaystyle \pi r^{2} $
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$ \displaystyle 3\pi r^{2} $
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$ \displaystyle 4\pi r^{2} $
C
Correct answer
Explanation
A hemisphere has a curved surface area of 2*pi*r^2 and a flat circular base of pi*r^2. Total surface area = 3*pi*r^2.
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$ \displaystyle \frac{1000}{3}\pi cm^{3} $
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$ \displaystyle \frac{500}{3}\pi cm^{3} $
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$ \displaystyle \frac{250}{3}\pi cm^{3} $
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$ \displaystyle \frac{125}{3}\pi cm^{3} $
D
Correct answer
Explanation
The cone is cut at the midpoint of the height. The smaller cone has height 5 and radius 5 (by similar triangles). Volume = (1/3) * pi * r^2 * h = (1/3) * pi * 5^2 * 5 = 125/3 * pi.