Joe has exactly enough paint to paint the surface of a cube whose side length is 2. It turns out that this is also exactly enough paint to paint the outer surface of a hemisphere. What is the radius of the hemisphere?
Surface of cube 2 x 2 x 6 = 24 units2
The surface of a sphere with TWICE this surface area (since we are painting only 1/2 of the sphere ) = 4 pi r2 = 48 units2
4 pi r2 = 48
r = sqrt( 48/4pi) = sqrt (12/pi) = 2 sqrt (3/pi)