Square pyramid
In geometry, a square pyramid is a pyramid having a square base. If the apex is perpendicularly above the center of the square, it is a right square pyramid, and has "C" symmetry. If all edge lengths are equal, it is an equilateral square pyramid, the Johnson solid J. General square pyramid. A possibly oblique square pyramid with base length "l" and perpendicular height "h" has volume: Right square pyramid. In a right square pyramid, all the lateral edges have the same length, and the sides other than the base are congruent isosceles triangles. A right square pyramid  with base length "l" and height "h" has surface area and volume: The lateral edge length is: the slant height is: The dihedral angles are: Equilateral square pyramid, Johnson solid J. If all edges have the same length, then the sides are equilateral triangles, and the pyramid is an equilateral square pyramid, Johnson solid J. The Johnson square pyramid can be characterized by a single edge length parameter "l". The height "h" (from the midpoint of the square to the apex), the surface area "A" (including all five faces), and the volume "V" of an equilateral square pyramid are: The  dihedral angles of an equilateral square pyramid are: Graph. A square pyramid can be represented by the wheel graph W. Related polyhedra and honeycombs. "Square pyramids" fill space with tetrahedra, truncated cubes, or cuboctahedra. Dual polyhedron. The square pyramid is topologically a self-dual polyhedron. The dual's edge lengths are different due to the polar reciprocation.