Question

A sphere and a cylinder have the same radius and height. The volume of the cylinder is 21 meters cubed. A sphere with height h and radius r. A cylinder with height h and radius r. What is the volume of the sphere?

Answer 1

c. 14 cm

Explanation:

Answer 2

We have been given that a sphere and a cylinder have the same radius and height. The volume of the cylinder is 21 meters cubed. We are asked to find the volume of the sphere.

We know that height of sphere is equal to its radius. This means that
`r=h`.

`\text{Volume of sphere}=(4)/(3)\pi r^3`

`\text{Volume of cylinder}=\pi r^2 h`

Using
`r=h`, we will get:

`\text{Volume of cylinder}=\pi r^2\cdot r`

`\text{Volume of cylinder}=\pi r^3`

Upon comparing volume of sphere and volume of cylinder, we can see that volume of sphere is
`(4)/(3)` times volume of cylinder.

`\pi r^3=21`

`(4)/(3)\pi r^3=(4)/(3)\cdot 21`

`(4)/(3)\pi r^3=4\cdot 7`

`(4)/(3)\pi r^3=28`

Therefore, the volume of the sphere would be 28 cubic meters.