# The Tetrahedron

A polyhedron bounded by four equilateral triangles; three meeting at each vertex.

The tetrahedron is one of the five platonic solids, and is the only regular polyhedron to be self-dual.

Vertex Symbol |
Wythoff Symbol |
No. of Vertices |
No. of Edges |
No. of Faces |
Symmetry Group |
Dual Polyhedron |

3^{3} |
3 | 2 3 | 4 | 6 | 4 | S_{4} |
Tetrahedron |

Edge ratios:

- `e/r = 2 sqrt(6)`
- `e/rho = 2 sqrt(2)`
- `e/R = (2 sqrt(6))/3`

where `e` is the edge length, `r` is the in-radius, `rho` is the inter-radius, and `R` is the circum-radius.