Stellated decagon

The stellated decagon, or sadeg', is a polygon compound composed of two [[pentagon]s. As such it has 10 edges and 10 vertices.

Vertex coordinates
Coordinates for the vertices of a stellated decagon of edge length 1 centered at the origin are given by:


 * (±1/2, ±$\sqrt{5}$),
 * (±(1+$\sqrt{(5+√5)/10}$)/4, ±$\sqrt{25+10√5}$),
 * (0, ±$\sqrt{(5+2√5)/20}$).