Polyhedron with four faces.
The faces of all tetrahedra are triangles.
Properties
- A tetrahedron is a pyramide with a triangular base.
 - A tetrahedron has 4 vertices, 6 edges and 4 triangular faces.
 - If the tetrahedron is a regular tetrahedron, then its four faces are congruent equilateral triangles.
 - A tetrahedron with three right angles can be obtained from a cube or a right rectangular prism. It is called a trirectangular tetrahedron.
 
Formula
The following formulas can be used to calculate the volume V and the area A of a regular tetrahedron as a function of the edge length a:
- V = \(\dfrac{\sqrt{2}}{12}\)\(a^{3}\)
 - A = \(\sqrt{3}\)\(a^{2}\)