# Great tridecagram

Great tridecagram Rank2
TypeRegular
SpaceSpherical
Notation
Bowers style acronymGet
Coxeter diagramx13/5o
Schläfli symbol{13/5}
Elements
Edges13
Vertices13
Measures (edge length 1)
Circumradius$\frac{1}{2\sin\frac{5\pi}{13}} ≈ 0.53475$ Inradius$\frac{1}{2\tan\frac{5\pi}{13}} ≈ 0.18962$ Area$\frac{13}{4\tan\frac{5\pi}{13}} ≈ 1.23256$ Angle$\frac{3\pi}{13} ≈ 41.53846^\circ$ Central density5
Number of external pieces26
Level of complexity2
Related polytopes
ArmyTad, edge length $\frac{\sin\frac{\pi}{13}}{\sin\frac{5\pi}{13}}$ DualGreat tridecagram
ConjugatesTridecagon, Small tridecagram, Tridecagram, Medial tridecagram, Grand tridecagram
Convex coreTridecagon
Abstract & topological properties
Flag count26
Euler characteristic0
OrientableYes
Properties
SymmetryI2(13), order 26
ConvexNo
NatureTame

The great tridecagram is a non-convex polygon with 13 sides. It's created by taking the fourth stellation]] of a tridecagon. A regular great tridecagram has equal sides and equal angles.

It is one of five regular 13-sided star polygons, the other four being the small tridecagram, the tridecagram, the medial tridecagram, and the grand tridecagram.