# Grand tridecagram

Grand tridecagram Rank2
TypeRegular
SpaceSpherical
Notation
Bowers style acronymGat
Coxeter diagramx13/6o
Schläfli symbol{13/6}
Elements
Edges13
Vertices13
Measures (edge length 1)
Circumradius$\frac{1}{2\sin\frac{6\pi}{13}} ≈ 0.50367$ Inradius$\frac{1}{2\tan\frac{6\pi}{13}} ≈ 0.060711$ Area$\frac{13}{4\tan\frac{6\pi}{13}} ≈ 0.39462$ Angle$\frac{\pi}{13} ≈ 13.84615^\circ$ Central density6
Number of external pieces26
Level of complexity2
Related polytopes
ArmyTad, edge length $2\cos\frac{6\pi}{13}$ DualGrand tridecagram
ConjugatesTridecagon, Small tridecagram, Tridecagram, Medial tridecagram, Great tridecagram
Convex coreTridecagon
Abstract & topological properties
Flag count26
Euler characteristic0
OrientableYes
Properties
SymmetryI2(13), order 26
ConvexNo
NatureTame

The grand tridecagram is a non-convex polygon with 13 sides. It's created by taking the fifth stellation of a tridecagon. A regular grand 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 great tridecagram.