Pentahedron
In geometry, a pentahedron (plural: pentahedra) is a polyhedron with five faces. Since there are no facetransitive polyhedra with five sides and there are two distinct topological types, this term is less frequently used than tetrahedron or octahedron.
With regular polygon faces, the two topological forms are the square pyramid and triangular prism. Geometric variations with irregular faces can also be constructed.
Name  Picture  Vertices  Edges  Faces  Faces by type 

Square pyramid (Pyramid family) 
5  8  5  4 triangles 1 square 

Triangular prism (Prism family) 
6  9  5  2 triangles 3 squares 
The square pyramid can be seen as a degenerate triangular prism where one edge of its side edges is collapsed into a point, losing one edge and one vertex, and changing two squares into triangles.
An irregular pentahedron can be a nonconvex solid.
Hosohedron
There is a third topological polyhedral figure with 5 faces, degenerate as a polyhedron, it exists as a spherical tiling of digon faces, called a pentagonal hosohedron with Schläfli symbol {2,5}. It has 2 (antipodal point) vertices, 5 edges, and 5 digonal faces.
External links

This polyhedronrelated article is a stub. You can help Wikipedia by expanding it. 
HPTS  Area Progetti  EduSoft  JavaEdu  N.Saperi  Ass.Scuola..  TS BCTV  TS VideoRes  TSODP  TRTWE  