If a sphere is placed in a cylinder of the same diameter and with an height equal to the diameter and the vacant spaces are filled with sand, the sand will be found to fill exactly one-third of the cylinder after the sphere is removed.
Therefore, a sphere is equal to two-thirds of a cylinder of the same diameter and height.
Here the volume of the cylinder
The volume of the sphere
The volume of a sphere or , where is the radius and is the diameter of the sphere.
The volume of a hemisphere