A spherical sector is a solid of revolution enclosed by two radii from the center of a sphere. The
spherical sector may either be "open" and have a conical hole
(left figure; Beyer 1987), or may be a "closed" spherical
cone (right figure; Harris and Stocker 1998). The volume
of a spherical sector in either case is given by
where
is the vertical distance between where the upper and lower radii intersect
the sphere and
is the sphere's radius.
is the vertical distance between where the upper and lower radii intersect
the sphere and 
is the sphere's radius.
