10-2 step prism

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10-2 step prism
Cells10+10+10 phyllic disphenoids, 5 rhombic disphenoids
Faces20+20+20 scalene triangles, 10 isosceles triangles
Vertex figureRidge-ditriakis notch
Measures (circumradius , based on a uniform duoprism)
Edge lengths8-valence (10):
 4-valence (5): 2
 3-valence (10):
 4-valence (10):
 4-valence (10):
Central density1
Related polytopes
Dual10-2 gyrochoron
Abstract & topological properties
Flag count840
Euler characteristic0
SymmetryS2(I2(10)-2), order 20
Flag orbits42

The 10-2 step prism is a convex isogonal polychoron and a step prism. It has 5 rhombic disphenoids and 30 phyllic disphenoids of three kinds as cells, with 14 (2 rhombic and 12 phyllic disphenoids) joining at each vertex.

It is one of 4 isogonal polychora with 10 vertices, and the only one to have only step prism symmetry in its highest symmetry form.

Using the ratio method, the lowest possible ratio between the longest and shortest edges is 1: ≈ 1:1.73855.

Vertex coordinates[edit | edit source]

Coordinates for the vertices of a 10-2 step prism inscribed in a decagonal duoprism with base lengths a and b are given by:

  • (a*sin(πk/5), a*cos(πk/5), b*sin(2πk/5), b*cos(2πk/5)),

where k is an integer from 0 to 9. If the edge length differences are to be minimized, the ratio of a:b must be equivalent to 1: ≈ 1:1.61803.

External links[edit | edit source]