Reference Terms
from Wikipedia, the free encyclopedia


A tetrahedron (plural: tetrahedra) is a polyhedron composed of four triangular faces, three of which meet at each vertex.

A regular tetrahedron is one in which the four triangles are regular, or "equilateral," and is one of the Platonic solids.

The tetrahedron is unique among the uniform polyhedra in possessing no parallel faces.

Note:   The above text is excerpted from the Wikipedia article "Tetrahedron", which has been released under the GNU Free Documentation License.
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May 25, 2017

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