A sphere and a right cylinder have the same radius and volume. The cylinder has a height of 3 inches. Find the radius.

Answer 1

Vs = (4/3) pi r^3
Vc = pi r^2 h where h = 3
so
4/3 pi r^3 = pi r^2 h
4 r^3 = 3 r^2 * 3
r = (9/4)

Answer 2

cylinder volume = sphere volume ... π r^2 h = 4/3 π r^3

dividing by (π r^2) ... h = 4/3 r