Regular polygon

Regular polygon
Regular triangle
Regular square
Regular pentagon
Regular hexagon
Regular heptagon
Regular octagon
Regular nonagon
Regular dodecagon
Edges and vertices
Schläfli symbol
Coxeter–Dynkin diagram
Symmetry groupDn, order 2n
Dual polygonSelf-dual
Area
(with side length )
Internal angle
Internal angle sum
Inscribed circle diameter
Circumscribed circle diameter
PropertiesConvex, cyclic, equilateral, isogonal, isotoxal

In Euclidean geometry, a regular polygon is a polygon that is direct equiangular (all angles are equal in measure) and equilateral (all sides have the same length). Regular polygons may be either convex, star or skew. In the limit, a sequence of regular polygons with an increasing number of sides approximates a circle, if the perimeter or area is fixed, or a regular apeirogon (effectively a straight line), if the edge length is fixed.