a cone is 8 cm high and radius is 2 cm.the cone is melt and recast into a sphere.find diameter of sphere.

volume of anything pointy with straight sides = (1/3) height * area of base

so
V = (1/3)(8)(4) pi

for sphere
V = (4/3) pi r^3

so
(4/3) pi r^3 = (1/3)(32 pi)

r^3 = 8

r = 2
diameter = 2 r = 4 cm