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 $18$ and the height of the cylinder is $21$ . If the volume of the solid is $420 pi$ , what is the area of the base of the cylinder?

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Answer 1 · 2017-01-12T09:16:02

The area is $=48.9u^2$

The volume of the cylinder $=$ area of base $*$ height

The volume of the cone $=1/3*$ area of base $*$ height

Let $a=$ area of the base

Volume of the cone $=1/3*a*18=6a$

Volume of cylinder $=a*21=21a$

Total $=6a+21a=27a=420pi$

$a=420/27pi=48.9 u^2$

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 18 18 and the height of the cylinder is 21 21 . If the volume of the solid is 420 pi420 pi, what is the area of the base of the cylinder?