Augmented dodecahedron

From HandWiki
Short description: 58th Johnson solid (16 faces)
Augmented dodecahedron
TypeJohnson
J57J58J59
Faces5 triangles
11 pentagons
Edges35
Vertices21
Vertex configuration3.5(53)
5(32.52)
1(35)
Symmetry groupC5v
Propertiesconvex
Net

In geometry, the augmented dodecahedron is a Johnson solid combining a regular dodecahedron and a pentagonal pyramid. File:J58 augmented dodecahedron.stl

Construction

An augmented dodecahedron is constructed from a regular dodecahedron, a twelve-sided polyhedron with regular pentagons, by attaching a regular-faced pentagonal pyramid to one of the regular dodecahedron's faces; the regular polygons mean that all of its internal angles and edges are equal. The resulting polyhedron covers one pentagon from a dodecahedron with five equilateral triangles from the pyramid. Ergo, the augmented dodecahedron has eleven pentagonal faces and five equilateral triangular faces, totaling sixteen faces.[1] The augmented is Johnson solid, a convex polyhedron with regular faces, enumerated as the fifty-eighth J58.[2]

Properties

The surface area of an augmented dodecahedron A is obtained by summing the area of its faces, eleven regular pentagons and five equilateral triangles. Its volume V is obtained by adding the volume of a regular dodecahedron and a pentagonal pyramid, as suggested by the construction:[1] A=1125+1054a2+534a221.09a2,V=15+754a3+5+524a37.965a3.

References

  1. 1.0 1.1 Berman, Martin (1971). "Regular-faced convex polyhedra". Journal of the Franklin Institute 291 (5): 329–352. doi:10.1016/0016-0032(71)90071-8. 
  2. Francis, Darryl (August 2013). "Johnson solids & their acronyms". Word Ways 46 (3): 177. https://digitalcommons.butler.edu/wordways/vol46/iss3/9/.