Two spheres of copper, of radii is 1 cm. and 2 cm. respectively, are melted in to a cylinder of radius 1 cm. Find the altitude of the cylinder.

Answer 1

volume of the 2 spheres
= (4/3)π (1^3 + 2^3)
= (4/3)π(9) = 12π cm^3

volume of cylinder = π r^2 h
12π = π(r^2)(1)
r^2 = 12
r = √12 or 2√3 cm = appr 3.464 cm

Answer 2

4/3? where is it come from?