<sod>Since this is a unit sphere, the lengths {{math|''a'', ''b''}}, and {{math|''c''}} are simply equal to the angles (in [[radian]]s) subtended by those sides from the center of the sphere (for a non-unit sphere, they are the distances divided by the radius).  As a special case, for {{math|''C'' {{=}} {{sfrac|π|2}}}}, then {{math|cos ''C'' {{=}} 0}}, and one obtains the spherical analogue of the [[Pythagorean theorem]]:<eod>
<sod>Since this is a unit sphere, the lengths {{math|''a'', ''b''}}, and {{math|''c''}} are simply equal to the angles (in [[radian]]s) subtended by those sides from the center of the sphere (for a non-unit sphere, the lengths are the subtended angles times the radius).  As a special case, for {{math|''C'' {{=}} {{sfrac|π|2}}}}, then {{math|cos ''C'' {{=}} 0}}, and one obtains the spherical analogue of the [[Pythagorean theorem]]:<eod>