Question

504 cones, each of diameter 3.5 cm and height 3 cm, are melted and recast into a metallic sphere. Find the diameter of the sphere and hence find its area.

Answer 1

volume of 504 cone=volume of sphere formed
let the radius of sphere be r
504×1/3×π×r'^2×h=4/3×π×r^3
504×35/20×35/20×3=4r^3
( 63×7×7×3)/4×2=r^3
7×3×3×7×7×3/2×2×2=r^3
21/2=r

radius of sphere willbe 21/2cm