Question

The volume of a right cone is 700 pi units. If its height is 21 units,
find its radius.

Answer 1

Explanation:

V=1/3 πr²h

700 π=1/3 πr²×21

r²=100

r=√100=10 units

Answer 2

r = 10

Explanation:

Using the formula:

`V = \pi r^(2) (h)/(3)`

We make r the subject to get:

`r = \sqrt{3 (V)/(\pi h) }`

Now we substitute values given and simplify:

r =
`\sqrt{3 (700\pi )/(21\pi ) }`

We can cancel out pi from top and bottom:

r =
`\sqrt{3 (700 )/(21 ) }`

We can do 700÷21 = 33.3333333333

Now we have:

`r = √(3 *33.3333333333)`
Simplify to get :

r ≈ 10