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 #2 #. 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 · 2017-02-21T07:10:36

The area of the base is #=31.4u^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+2)#

#90pi=a*9#

#a=90/9pi=10pi#

#a=31.4#