Triangular hebesphenorotunda

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File:J92 triangular hebesphenorotunda.stl
3D model of a triangular hebesphenorotunda

In geometry, the triangular hebesphenorotunda is a Johnson solid with 13 equilateral triangles, 3 squares, 3 regular pentagons, and 1 regular hexagon, meaning the total of its faces is 20.

Properties

The original name is attributed to Script error: No such module "Footnotes"., with two affixes. The prefix hebespheno- refers to a blunt wedge-like complex formed by three adjacent lunes, a figure where two equilateral triangles are attached at the opposite sides of a square, whereas the suffix (triangular) -rotunda refers to the complex of three equilateral triangles and three regular pentagons surrounding another equilateral triangle, which bears a structural resemblance to the pentagonal rotunda.[1]Template:R/superscript Therefore, the triangular hebesphenorotunda has twenty faces: thirteen equilateral triangles, three squares, three regular pentagons, and one regular hexagon.[2]Template:R/superscript The faces are all regular polygons, categorizing the triangular hebesphenorotunda as a Johnson solid, enumerated the last one J92.[3]Template:R/superscript It is an elementary polyhedron, meaning that it cannot be separated by a plane into two small regular-faced polyhedra.[4]Template:R/superscript

The surface area of a triangular hebesphenorotunda of edge length a is:[2]Template:R/superscript A=(3+141308+905+11475+305)a2≈16.389a2, and its volume is:[2]Template:R/superscript V=16(15+75)a3≈5.10875a3.

Cartesian coordinates

The triangular hebesphenorotunda with edge length 5−1 can be constructed by the union of the orbits of the Cartesian coordinates: (0,−2τ3,2τ3),(τ,13τ2,23)(τ,−τ3,23τ),(2τ,0,0), under the action of the group generated by rotation by 120° around the z-axis and the reflection about the yz-plane. Here, τ denotes the golden ratio.[5]Template:R/superscript

References

  1. ↑ Script error: No such module "citation/CS1"..
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  3. ↑ Script error: No such module "citation/CS1"..
  4. ↑ Script error: No such module "citation/CS1"..
  5. ↑ Script error: No such module "citation/CS1"..

External links

Template:Johnson solids navigator