Stellated decagram

The stellated decagram or sadag is a polygon compound composed of two pentagrams. As such it has 10 edges and 10 vertices.

It is the fourth stellation of the decagon.

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


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