The height of a solid cone is 12 cm and the area of the circular base is 64π cm2. A plane parallel to the base of the cone cuts through the cone 9 cm above the vertex of the cone, the area of the base of the new cone so formed is
We have,
Height of cone = 12cm
Area of circular base = 64π cm2
Height from the vertex of small cone = 9 cm
π r2 = 64π
r2= 64
Radius of base = 8cm
From similarity triangle = 
= R = 
R = radius of small cone
Area of small cone = πr2 = π(6)2 = 36π cm2
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