Hebesphenomegacorona

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Hebesphenomegacorona
File:Hebesphenomegacorona.png
TypeJohnson
J88J89J90
Faces3x2+3x4 triangles
1+2 squares
Edges33
Vertices14
Vertex configuration4(32.42)
2+2x2(35)
4(34.4)
Symmetry groupC2v
Propertiesconvex, elementary
Net
File:Johnson solid 89 net.png
File:J89 hebesphenomegacorona.stl
3D model of a hebesphenomegacorona

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

Properties

The hebesphenomegacorona is named by Johnson (1966) 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.[1] By joining both complexes together, the result polyhedron has 18 equilateral triangles and 3 squares, making 21 faces.[2]. 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.[3] It is an elementary polyhedron, meaning it cannot be separated by a plane into two small regular-faced polyhedra.[4] 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 6+932a210.7942a2, and its volume is 2.9129a3.[2]

Cartesian coordinates

Let a0.21684 be the second smallest positive root of the polynomial 26880x10+35328x925600x839680x7+6112x6+13696x5+2128x41808x31119x2+494x47 Then, Cartesian coordinates of a hebesphenomegacorona with edge length 2 are given by the union of the orbits of the points (1,1,21a2),(1+2a,1,0),(0,1+22a1a1,2a2+a11a2),(1,0,34a2),(0,2(34a2)(12a)+1+a2(1a)1+a,(2a1)34a22(1a)2(12a)2(1a)1+a) under the action of the group generated by reflections about the xz-plane and the yz-plane.[5]

References

  1. Johnson, N. W. (1966). "Convex polyhedra with regular faces". Canadian Journal of Mathematics. 18: 169–200. doi:10.4153/cjm-1966-021-8. MR 0185507. S2CID 122006114. Zbl 0132.14603.
  2. 2.0 2.1 Berman, M. (1971). "Regular-faced convex polyhedra". Journal of the Franklin Institute. 291 (5): 329–352. doi:10.1016/0016-0032(71)90071-8. MR 0290245.
  3. Francis, D. (August 2013). "Johnson solids & their acronyms". Word Ways. 46 (3): 177.
  4. Cromwell, P. R. (1997). Polyhedra. Cambridge University Press. p. 86–87, 89. ISBN 978-0-521-66405-9.
  5. Timofeenko, A. V. (2009). "The non-Platonic and non-Archimedean noncomposite polyhedra". Journal of Mathematical Science. 162 (5): 717. doi:10.1007/s10958-009-9655-0. S2CID 120114341.

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