In geometry, the elongated pyramids are an infinite set of polyhedra, constructed by adjoining an n-gonal pyramid to an n-gonal prism. Along with the set of pyramids, these figures are topologically self-dual. There are three elongated pyramids that are Johnson solids: Elongated triangular pyramid (J_7), Elongated square pyramid (J_8), and Elongated pentagonal pyramid (J_9). Higher forms can be constructed with isosceles triangles.