# Hendecagram

Hendecagram Rank2
TypeRegular
SpaceSpherical
Notation
Bowers style acronymHenge
Coxeter diagramx11/3o (     )
Schläfli symbol{11/3}
Elements
Edges11
Vertices11
Measures (edge length 1)
Circumradius$\frac{1}{2\sin\frac{3\pi}{11}} ≈ 0.66159$ Inradius$\frac{1}{2\tan\frac{3\pi}{11}} ≈ 0.43325$ Area$\frac{11}{4\tan\frac{3\pi}{11}} ≈ 2.38289$ Angle$\frac{5\pi}{11} ≈ 81.81818^\circ$ Central density3
Number of external pieces22
Level of complexity2
Related polytopes
ArmyHeng, edge length $\frac{\sin\frac{\pi}{11}}{\sin\frac{3\pi}{11}}$ DualHendecagram
ConjugatesHendecagon, small hendecagram, great hendecagram, grand hendecagram
Convex coreHendecagon
Abstract & topological properties
Flag count22
Euler characteristic0
OrientableYes
Properties
SymmetryI2(11), order 22
ConvexNo
NatureTame

The hendecagram also called the medial hendecagram, is a non-convex polygon with 11 sides. It's created by taking the second stellation of a hendecagon. A regular hendecagram has equal sides and equal angles.

It is one of four regular 11-sided star polygons, the other three being the small hendecagram, the great hendecagram, and the grand hendecagram. The name "hendecagram" is often used to describe any of these shapes.

## Vertex coordinates

The vertex coordinates for a hendecagram are the same as those of the hendecagon.