Question

The volume of a cylinder is 540 pi ft^3 the height is 15 ft. what is the diameter

a. 6
b.12
c.24
d.36​

Answer 1

b. 12

Explanation:

The volume of a cylinder is

`\pi {r}^(2) h`

Let us compose an equality and solve for the radius.

540pi = pi × r^2 × 15.

Divide both sides of the equation by 15pi.

r^2 = 36

r = +/- 6.

Length cannot be negative, so r = 6.

diameter = 2 × r. In this case,

d = 2 × 6 = 12.

The diameter is 12 ft.

Answer 2

12

Explanation:

Volume of cylinder is pi*r^2*h (this is equal to 540pi in this case)

So we have 540pi=pi*r^2*h

this means that 540=r^2*h (I just divided both sides by pi since both sides were being multiplied by pi)

The height,h, is 15 so plug in 540=r^2*15

Divide both sides by 15 giving 540/15=r^2

So r^2=36

So r=6

The diameter,d, is twice the radius, r.

So d=2(6)=12