**Theorem 1.3**: (Coxeter
[3]) Let 0 < k < n/2. The
angle at the points of an {n/k} star is 180 - 360k/n.

**proof**: The {n/k} star is a set of points on a circle, and
the angle at the point of the star is an inscribed angle whose
central angle is 360 - 2(360k/n).