Low of sines in spherical triangle

Description

A spherical polygon on the surface of the sphere is defined by a number of great circle arcs which are the intersection of the surface with planes through the centre of the sphere. Such polygons may have any number of sides. Three planes define a spherical triangle. There is a relation between the sines of the angles at the center of the sphere subtended by the three arcs of the spherical surface triangle and the sines of the surface angles opposite their respective arcs.

Related formulas

Variables

ASurface angle of the sherical triangle (radians)
αAngle at the center of the sphere (radians)
BSurface angle of the sherical triangle (radians)
βAngle at the center of the sphere (radians)