## The Tetrahedron

The Tetrahedron is a regular three-sided Pyramid. Its surface consists of four equilateral triangles and is therefore one of the five
** Platonic solids**.

The following elements of a tetrahedron are calculated if one of them is given:

- Edge a
- Apothem h
_{1} - Altitude h
_{2} - Circumradius r
_{u} - Inradius r
_{i} - Volume V
- Surface S

### Example:

Given: ¯¯¯¯¯¯ Circumradius rc = 1 Results: ¯¯¯¯¯¯¯ Edge a = 1,6329932 Apothem h1 = 1,4142136 Altitude h2 = 1,3333333 Inradius ri = 0,33333333 Volume V = 0,51320024 Surface S = 4,6188022

### See also:

Graphics 3DWikipedia: Platonic solid