# Small tridecagram

Small tridecagram Rank2
TypeRegular
SpaceSpherical
Notation
Bowers style acronymSat
Coxeter diagramx13/2o
Schläfli symbol{13/2}
Elements
Edges13
Vertices13
Measures (edge length 1)
Circumradius$\frac{1}{2\sin\frac{2\pi}{13}} ≈ 1.07510$ Inradius$\frac{1}{2\tan\frac{2\pi}{13}} ≈ 0.95267$ Area$\frac{13}{4\tan\frac{2\pi}{13}} ≈ 6.19236$ Angle$\frac{9\pi}{13} ≈ 124.61538^\circ$ Central density2
Number of external pieces26
Level of complexity2
Related polytopes
ArmyTad, edge length $\frac{1}{2\cos\frac{\pi}{13}}$ DualSmall tridecagram
ConjugatesTridecagon, Tridecagram, Medial tridecagram, Great tridecagram, Grand tridecagram
Convex coreTridecagon
Abstract & topological properties
Flag count22
Euler characteristic0
OrientableYes
Properties
SymmetryI2(13), order 26
ConvexNo
NatureTame

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

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