Tetrahedron
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(1) A general tetrahedron is any polyhedron having four faces. (2) The regular tetrahedron is the Platonic solid comprised of four equilateral triangles, four vertices, and six edges.
Tetrahedron is a middle school-level concept.
Prerequisites
| Platonic Solid: | The Platonic solids are the five convex solids composed of identical regular polygons. |
| Regular Polygon: | A regular polygon is a polygon in which the sides are all the same length and the angles all have the same measure. |