Question

The volume of a cylinder is 980pi in3. The radius is 7 in. What is its height?

A) 10 in
B) 140 in
C) 70 in
D) 20 in

Answer 1

h ≈ 20 inches

Explanation:

Given volume 980 pi inches cubed and radius 7 inches.

Using the height formula for right cylinder

h = V/π r^2

h = 3078.78/π7^2

h ≈ 20 inches

Answer 2

D) 20 in

Explanation:

The volume of a cylinder is given by

V = pi r^2 h where r is the radius and h is the height

Substituting what we know

980 pi = pi (7)^2 h

Divide each side by pi

980 pi /pi= pi 49 h/pi

980 = 49h

Divide each side by 49

980/49 = 49h/49

20 =h