Hebesphenomegacorona Explained

Type:Johnson
Faces:3x2+3x4 triangles
1+2 squares
Edges:33
Vertices:14
Net:Johnson solid 89 net.png

In geometry, the hebesphenomegacorona is a Johnson solid with 18 equilateral triangles and 3 squares as its faces.

Properties

The hebesphenomegacorona is named by in which he used the prefix hebespheno- referring to a blunt wedge-like complex formed by three adjacent lunes - a square with equilateral triangles attached on its opposite sides. The suffix -megacorona refers to a crownlike complex of 12 triangles. By joining both complexes together, the result polyhedron has 18 equilateral triangles and 3 squares, making 21 faces.. All of its faces are regular polygons, categorizing the hebesphenomegacorona as a Johnson solid - a convex polyhedron in which all of its faces are regular polygons - enumerated as 89th Johnson solid

J89

. It is elementary, meaning it cannot be separated by a plane into two small regular-faced polyhedra.

The surface area of a hebesphenomegacorona with edge length

a

can be determined by adding the area of its faces, 18 equilateral triangles and 3 squares \fraca^2 \approx 10.7942a^2, and its volume is

2.9129a3

.

Cartesian coordinates

Let

a0.21684

be the second smallest positive root of the polynomial \begin &26880x^ + 35328x^9 - 25600x^8 - 39680x^7 + 6112x^6 \\ &\quad + 13696x^5 + 2128x^4 - 1808x^3 - 1119x^2 + 494x - 47 \endThen, Cartesian coordinates of a hebesphenomegacorona with edge length 2 are given by the union of the orbits of the points \begin &\left(1,1,2\sqrt\right),\ \left(1+2a,1,0\right),\ \left(0,1+\sqrt\sqrt,-\frac\right),\ \left(1,0,-\sqrt\right), \\ &\left(0,\frac,\frac-\frac\right) \endunder the action of the group generated by reflections about the xz-plane and the yz-plane