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HELP!

Select the correct answer.
Two equal spheres with the maximum possible radius are carved out of a right cylinder.
Find the ratio of the volume of one sphere to the volume of the right cylinder.
A.
1 : 1
B.
1 : 3
C.
2 : 3
D.
3 : 1

HELP! Select the correct answer. Two equal spheres with the maximum possible radius-example-1

1 Answer

3 votes

Answer:

The ratio of the volume of one sphere to the volume of the right cylinder is 1 : 3 ⇒ answer B

Explanation:

* Lets explain how to solve the problem

- The spheres touch the two bases of the cylinder

∴ The height of the cylinder = the diameters of the two spheres

∵ The diameter of the sphere = twice its radius

∴ The diameter of the sphere = 2r, where r is the radius of the sphere

∵ The height of the cylinder = 2 × diameter of the sphere

∴ The height of the cylinder = 2 × 2r = 4r

- The spheres touch the curved surface of the cylinder, that means

the diameter of the sphere equal the diameter of the cylinder

∴ The maximum possible radius of the sphere is the radius of the

cylinder

∵ The radius of the sphere is r

∴ The radius of the cylinder is r

- The volume of the cylinder is πr²h and the volume of the sphere is

4/3 πr³

∵ The height of the cylinder = 4r ⇒ proved up

∵ The radius of the cylinder = r

∵ The volume of the cylinder = πr²h

∴ The volume of the cylinder = πr²(4r) = 4πr³

∵ The radius of the sphere = r

∵ The volume of the sphere = 4/3 πr³

∴ The ratio of the volume of one sphere to the volume of the right

cylinder = 4/3 πr³ : 4 πr³

- Divide both terms of the ratio by 4 πr³

∴ The ratio = 1/3 : 1

- Multiply both terms of the ratio by 3

∴ The ratio = 1 : 3

∴ The ratio of the volume of one sphere to the volume of the right

cylinder is 1 : 3

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