Heptagonal-enneagonal duoprism

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Heptagonal-enneagonal duoprism
Rank4
TypeUniform
Notation
Bowers style acronymHeendip
Coxeter diagramx7o x9o (File:CDel node 1.pngFile:CDel 7.pngFile:CDel node.pngFile:CDel 2.pngFile:CDel node 1.pngFile:CDel 9.pngFile:CDel node.png)
Elements
Cells9 heptagonal prisms, 7 enneagonal prisms
Faces63 squares, 9 heptagons, 7 enneagons
Edges63+63
Vertices63
Vertex figureDigonal disphenoid, edge lengths 2cos(π/7) (base 1), 2cos(π/9) (base 2), and 2 (sides)
Measures (edge length 1)
Circumradius
Hypervolume
Dichoral anglesHep–7–hep: 140°
 Ep–9–ep:
 Hep–4–ep: 90°
Central density1
Number of external pieces16
Level of complexity6
Related polytopes
ArmyHeendip
RegimentHeendip
DualHeptagonal-enneagonal duotegum
ConjugatesHeptagonal-enneagrammic duoprism,
Heptagonal-great enneagrammic duoprism,
Heptagrammic-enneagonal duoprism,
Heptagrammic-enneagrammic duoprism,
Heptagrammic-great enneagrammic duoprism,
Great heptagrammic-enneagonal duoprism,
Great heptagrammic-enneagrammic duoprism,
Great heptagrammic-great enneagrammic duoprism
Abstract & topological properties
Flag count1512
Euler characteristic0
OrientableYes
Properties
SymmetryI2(7)×I2(9), order 252
Flag orbits6
ConvexYes
NatureTame

The heptagonal-enneagonal duoprism or heendip, also known as the 7-9 duoprism, is a uniform duoprism that consists of 7 enneagonal prisms and 9 heptagonal prisms, with two of each joining at each vertex.

Gallery[edit | edit source]

Vertex coordinates[edit | edit source]

The coordinates of a heptagonal-enneagonal duoprism, centered at the origin and with edge length 4sin(π/7)sin(π/9), are given by:

  • ,
  • ,
  • ,
  • ,
  • ,
  • ,

where j = 2, 4, 8 and k = 2, 4, 6.

External links[edit | edit source]