# Tetratriangle

Tetratriangle Rank2
TypeRegular
SpaceSpherical
Notation
Bowers style acronymTetri
Schläfli symbol{12/4}
Elements
Components4 triangles
Edges12
Vertices12
Measures (edge length 1)
Circumradius$\frac{\sqrt3}{3} ≈ 0.57735$ Inradius$\frac{\sqrt3}{6} ≈ 0.28868$ Area$\sqrt3 ≈ 1.73205$ Angle60°
Central density4
Number of external pieces24
Level of complexity2
Related polytopes
ArmyDog
DualTetratriangle
ConjugateTetratriangle
Convex coreDodecagon
Abstract & topological properties
Euler characteristic0
OrientableYes
Properties
SymmetryI2(12), order 24
ConvexNo
NatureTame

The tetratriangle, or tetri, is a polygon compound composed of 4 triangles. As such it has 12 edges and 12 vertices.

It is the third stellation of the dodecagon.

Its quotient prismatic equivalent is the triangular tetrahedroorthowedge, which is five-dimensional.

## Vertex coordinates

Coordinates for the vertices of a tetratriangle of edge length 1 centered at the origin are given by:

• $\left(±\frac12,\,±\frac{\sqrt3}{6}\right),$ • $\left(0,\,±\frac{\sqrt3}{3}\right),$ • $\left(±\frac{\sqrt3}{6},\,±\frac12\right),$ • $\left(±\frac{\sqrt3}{3},\,0\right).$ 