Elongated triangular cupola

In geometry, the elongated triangular cupola is one of the Johnson solids (J_18). As the name suggests, it can be constructed by elongating a triangular cupola (J_3) by attaching a hexagonal prism to its base. The following formulae for volume and surface area can be used if all faces are regular, with edge length a: The dual of the elongated triangular cupola has 15 faces: 6 isosceles triangles, 3 rhombi, and 6 quadrilaterals. The elongated triangular cupola can form a tessellation of space with tetrahedra and square pyramids.