Enneagonal-decagonal duoprism

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Enneagonal-decagonal duoprism
Rank4
TypeUniform
Notation
Bowers style acronymEdidip
Coxeter diagramx9o x10o ()
Elements
Cells10 enneagonal prisms, 9 decagonal prisms
Faces90 squares, 10 enneagons, 9 decagons
Edges90+90
Vertices90
Vertex figureDigonal disphenoid, edge lengths 2cos(π/9) (base 1), (5+5)/2 (base 2), and 2 (sides)
Measures (edge length 1)
Circumradius
Hypervolume
Dichoral anglesEp–9–ep: 144°
 Dip–10–dip: 140°
 Ep–4–dip: 90°
Central density1
Number of external pieces19
Level of complexity6
Related polytopes
ArmyEdidip
RegimentEdidip
DualEnneagonal-decagonal duotegum
ConjugatesEnneagonal-decagrammic duoprism, Enneagrammic-decagonal duoprism, Enneagrammic-decagrammic duoprism, Great enneagrammic-decagonal duoprism, Great enneagrammic-decagrammic duoprism
Abstract & topological properties
Euler characteristic0
OrientableYes
Properties
SymmetryI2(9)×I2(10), order 360
ConvexYes
NatureTame

The enneagonal-decagonal duoprism or edidip, also known as the 9-10 duoprism, is a uniform duoprism that consists of 9 decagonal prisms and 10 enneagonal prisms, with two of each joining at each vertex.

Vertex coordinates[edit | edit source]

The coordinates of an enneagonal-decagonal duoprism, centered at the origin and with edge length 2sin(π/9), are given by:

where j = 2, 4, 8.

Representations[edit | edit source]

An enneagonal-decagonal duoprism has the following Coxeter diagrams:

  • x9o x10o (full symmetry)
  • x5x x9o () (decagons as dipentagons)

External links[edit | edit source]