Pentagrammic-enneagonal duoprism |
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Rank | 4 |
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Type | Uniform |
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Notation |
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Bowers style acronym | Starendip |
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Coxeter diagram | x5/2o x9o () |
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Elements |
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Cells | 9 pentagrammic prisms, 5 enneagonal prisms |
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Faces | 45 squares, 9 pentagrams, 5 enneagons |
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Edges | 45+45 |
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Vertices | 45 |
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Vertex figure | Digonal disphenoid, edge lengths (√5–1)/2 (base 1), 2cos(π/9) (base 2), √2 (sides) |
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Measures (edge length 1) |
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Circumradius | |
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Hypervolume | |
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Dichoral angles | Stip–5/2–stip: 140° |
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| Stip–4–ep: 90° |
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| Ep–9–ep: 36° |
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Central density | 2 |
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Number of external pieces | 19 |
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Level of complexity | 12 |
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Related polytopes |
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Army | Semi-uniform peendip |
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Regiment | Starendip |
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Dual | Pentagrammic-enneagonal duotegum |
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Conjugates | Pentagonal-enneagonal duoprism, Pentagonal-enneagrammic duoprism, Pentagonal-great enneagrammic duoprism, Pentagrammic-enneagrammic duoprism, Pentagrammic-great enneagrammic duoprism |
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Abstract & topological properties |
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Euler characteristic | 0 |
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Orientable | Yes |
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Properties |
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Symmetry | H2×I2(9), order 180 |
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Convex | No |
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Nature | Tame |
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The pentagrammic-enneagonal duoprism, also known as starendip or the 5/2-9 duoprism, is a uniform duoprism that consists of 9 pentagrammic prisms and 5 enneagonal prisms, with 2 of each at each vertex.
The coordinates of a pentagrammic-enneagonal duoprism, centered at the origin and with edge length 2sin(π/9), are given by:
where j = 2, 4, 8.