A triangular pyramid has six edges. The base of the pyramid is a triangle and the three sides are also triangles. Another name for a triangular pyramid is a tetrahedron.
A regular tetrahedron consists of equilateral triangles while an irregular tetrahedron does not. Triangular pyramids have four faces and four vertices. The tetrahedron is the only Platonic solid with no parallel faces. The Platonic solids are convex polyhedra where each face of the shape is the same regular polygon. The five solids are the cube, tetrahedron, dodecahedron, icosahedron, and octahedron. Euclid proved there are only five solids in three dimensions. Plato and ancient Greeks equated the tetrahedron with the element of fire.