A solid consists of a cone on top of a cylinder with a radius equal to that of the cone. The height of the cone is 36 and the height of the cylinder is 4. If the volume of the solid is 144π, what is the area of the base of the cylinder?

1 Answer
Sep 9, 2016

Base area of cylinder =9π

Explanation:

As the cone and the cylinder have a same radius, their base area is also the same.

Let base area = A = πr2.
cone volume =πr2×h13, (h1=36) = A×363=12A
cylinder volume = πr2×h2, (h2=4) =A×4=4A

solid volume = cone volume + cylinder volume
144π=12A+4A=16A

A=144π16=9π