Spherical segment
In geometry, a spherical segment is the solid defined by cutting a sphere or a ball with a pair of parallel planes.
It can be thought of as a spherical cap with the top truncated, and so it corresponds to a spherical frustum.
The surface of the spherical segment is called spherical zone.
If the radius of the sphere is called R, the radii of the spherical segment bases are r1 and r2, and the height of the segment called h, then the volume of the spherical segment is
The curved surface area of the spherical zone—which excludes the top and bottom bases—is given by
