In geometry, the elongated pentagonal cupola is one of the Johnson solids (). As the name suggests, it can be constructed by elongating a pentagonal cupola () by attaching a decagonal prism to its base. The solid can also be seen as an elongated pentagonal orthobicupola () with its "lid" (another pentagonal cupola) removed. Formulas The following formulas for the volume and surface area can be used if all faces are regular, with edge length a: Dual polyhedron The dual of the elongated pentagonal cupola has 25 faces: 10 isosceles triangles, 5 kites, and 10 quadrilaterals. References External links Johnson solids