In geometry, the elongated pentagonal pyramid is one of the Johnson solids (). As the name suggests, it can be constructed by elongating a pentagonal pyramid () by attaching a pentagonal prism to its base. Formulae The following formulae for the height (), surface area () and volume () can be used if all faces are regular, with edge length : Dual polyhedron The dual of the elongated pentagonal pyramid has 11 faces: 5 triangular, 1 pentagonal and 5 trapezoidal. It is topologically identical to the Johnson solid. See also Elongated pentagonal bipyramid References External links Johnson solids Self-dual polyhedra Pyramids and bipyramids