A water balloon has a diameter of 6 inches. How many cubic inches of water does it contain when it is 3/4 full

Below are the choices that can be found from other sources:

A) 36 pi

B) 6 pi

C) 27 pi

D) 216 pi

E) 48 pi

A sphere's volume is (4/3) * pi*r^3.

The diameter of the balloon is 6 inches. The diameter is twice the radius. The radius is 3 inches.

(4/3) * pi*3^3 = 36 * pi

But the balloon is only 3/4 full. So

36 * (3/4) * pi = 27 * pi.

The balloon has 27 pi cubic inches of water.