four-sided polyhedron

A tetrahedron (triangular pyramid) is a three-dimensional shape. It has four corners. It looks like a pyramid. It has six equally long edges, four corners and four equilateral triangular faces. Every two edges meet on one of those corners forming a sixty-degree angle. All of its sides are triangles.

A rotating tetrahedron

Formulas for a regular tetrahedronEdit

A regular tetrahedron is a tetrahedron where all of its edges are the same length. If the length of an edge is a:

Surface area[1]  
Face area  
Height[2]   and  
Volume[1]   and  


  1. 1.0 1.1 Coxeter, Harold Scott MacDonald; Regular Polytopes, Methuen and Co., 1948, Table I(i)
  2. Köller, Jürgen, "Tetrahedron", Mathematische Basteleien, 2001