Edges 80 Symmetry group D5h | Vertices 40 | |
 | ||
Type Johnson
J41 - J42 - J43 Faces 2.10 triangles
2.5 squares
2+10 pentagons Vertex configuration 20(3.4.5)
2.10(3.5.3.5) | ||
In geometry, the elongated pentagonal orthobirotunda is one of the Johnson solids (J42). As the name suggests, it can be constructed by elongating a pentagonal orthobirotunda (J34) by inserting a decagonal prism between its congruent halves. Rotating one of the pentagonal rotundae (J6) through 36 degrees before inserting the prism yields the elongated pentagonal gyrobirotunda (J43).
A Johnson solid is one of 92 strictly convex polyhedra that have regular faces but are not uniform (that is, they are not Platonic solids, Archimedean solids, prisms or antiprisms). They were named by Norman Johnson, who first listed these polyhedra in 1966.
Formulae
The following formulae for volume and surface area can be used if all faces are regular, with edge length a: