Question

The volume of a cone is 75π cm3 and the height is 9 cm. What is the radius of the cone? A. 15 cm B. 5 cm C. 25 cm D. 10 cm

Answer 1

75pie= 1/3(pie r2)(9)
75pie=3(pie r²)
25pie=pie r²
√25 =√r²
r=5

Answer 2

We are given with the Volume of the cone , and height of the cone ,

and it is asking about the radius of the cone

Now first of all , we should remember the formula for Volume of the cone

Volume of the cone =
`(1)/(3) \pi r^(2) h`

Let's plug the values given

`75\pi= (1)/(3) \pi r^(2) (9)`

Divide both sides by
`\pi`

`75= (1)/(3) r^(2) (9)`

Simplifying we get

`75= r^(2) (3)`

Divide both sides by 3

`25= r^(2)`

Takeing square root on both sides

So

r=5

Hence radius is 5 cm

Option B is the correct one