Regular polygons

Polygons all angles of which are equal and all sides of which are equal. Cf. Polygon for more details.

Comments

In other words, a regular polygon is a polygon whose vertices all lie on one circle while its sides all touch a concentric circle. If the polygon is convex and has vertices, it is called an -gon, and is denoted by . If it is non-convex and its sides surround its centre times, it is called a star polygon, or a star -gon of density , and is denoted by . For instance, the pentagram is .

References

[a1]	H.S.M. Coxeter, "Regular complex polytopes" , Cambridge Univ. Press (1990) pp. Chapt. 1