The measure of each internal angle of a regular tridecagon is approximately 152.308 degrees, and the area with side length a is given by As 13 is a Pierpont prime but not a Fermat prime, the regular tridecagon cannot be constructed using a compass and straightedge.

according to Andrew M. Gleason,[1] based on the angle trisection by means of the Tomahawk (light blue).

An approximate construction of a regular tridecagon using straightedge and compass is shown here.

At a circumscribed circle of radius r = 1 billion km (a distance which would take light approximately 55 minutes to travel), the absolute error on the side length constructed would be less than 1 mm.

Cyclic symmetries in the middle column are labeled as g for their central gyration orders.