Find an expression in terms of radius r for the ratio of surface area to volume
for each of the following objects, given
that their volume is equal to that of the
sphere of radius r:
i A cube.
ii A cylinder with two half-spheres
attached at its bases, and height of
cylinder equal to five times the radius
of its base.
iii Hence, if the sphere has unit volume,
find how many times more surface
area each object will have than the
sphere.