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 $21$ and the height of the cylinder is $11$ . If the volume of the solid is $90 pi$ , what is the area of the base of the cylinder?

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Answer 1 · 2017-02-16T07:38:28

The area of the base is $=5pi=15.71u^2$

Let $a=$ area of the base

Volume of cone is $V_(co)=1/3*a*h_(co)$

Volume of cylinder is $V_(cy)=a*h_(cy)$

Total volume

$V=V_(co)+V_(cy)$

$V=1/3ah_(co)+ah_(cy)$

$90pi=a(1/3*21+11)$

$90pi=a*18$

$a=90/18pi=5pi$

$a=15.71$

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 21 21 and the height of the cylinder is 11 11 . If the volume of the solid is 90 pi90 pi, what is the area of the base of the cylinder?