The volume of a sphere is found by multiplying four-thirds by pi by radius cubed. The Greek mathematician Archimedes first derived this formula. He also found that the surface area of a sphere equals four by pi by radius squared.
Geometrically, a sphere is defined as the set of all points equidistant from a given center point in three dimensions. Of all geometric solids, a sphere has the least amount of surface area for a given volume. For that reason, soap film tends to pull itself into a spherical bubble, because surface tension tends to minimize the surface area around the enclosed volume of air.