Heptagon

Regular heptagon
A regular heptagon
TypeRegular polygon
Edges and vertices7
Schläfli symbol{7}
Coxeter–Dynkin diagrams
Symmetry groupDihedral (D7), order 2×7
Internal angle (degrees)≈128.571°
PropertiesConvex, cyclic, equilateral, isogonal, isotoxal
Dual polygonSelf

In geometry, a heptagon or septagon is a seven-sided polygon or 7-gon.

The heptagon is sometimes referred to as the septagon, using "sept-" (an elision of septua-, a Latin-derived numerical prefix, rather than hepta-, a Greek-derived numerical prefix; both are cognate) together with the Greek suffix "-agon" meaning angle.