A polyhedron is a three-dimensional surface composed of at least four flat faces which encloses a region of space. These faces intersect in edges and vertices. Polyhedra are 3-D analogues of polygons. They can be thought of as sets of ordered triples.
Polyhedra can be convex or concave]].
Number of sides
They have congruent faces, angles, and edges. Only regular tetrahedra, hexahedra (cubes), octahedra, dodecahedra, and icosahedra exist. (In addition, a sphere could be thought of a polyhedron with an infinite number of faces.)
The polyhedra most commonly encountered include:
- tetrahedron - 4 faces
- hexahedron - 6 faces
Prisms and pyramids can be polyhedra.
The surface area of a polyhedron is the sum of its sides.
- Polyhedral solids are the union of a polyhedron and the space that it encloses.
This article is a stub. Help us out by expanding it.