Tetrahedron

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The tetrahedron or triangular pyramid is the simplest polyhedron. Tetrahedra have 4 vertices, 4 triangular faces and 6 edges. 3 faces and 3 edges meet at each vertex.

Any 4 points chosen in space will be the vertices of a tetrahedron as long as they do not all lie on a single plane.

Regular tetrahedra, in which all edges have equal length and all faces are congruent equilateral triangles, are one of the five types of Platonic solids.