Decagram (geometry)

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Regular decagram
Regular star polygon 10-3.svg
A regular decagram
Type Regular polygon
Edges and vertices 10
Schläfli symbol {10/3}
Coxeter diagram CDel node 1.pngCDel 10.pngCDel rat.pngCDel d3.pngCDel node.png
CDel node 1.pngCDel 5-3.pngCDel node 1.png
Symmetry group Dihedral (D10)
Internal angle (degrees) 72°
Dual polygon self
Properties star, cyclic, equilateral, isogonal, isotoxal

In geometry, a decagram is a 10-sided star polygon. There is one regular decagram, containing the vertices of a regular decagon, but connected by every third point. Its Schläfli symbol is {10/3}.[1]

For a regular decagram with unit edge lengths, the proportions of the crossing points on each edge are as shown below.

Decagram lengths.svg

See also[edit]


  1. ^ Barnes, John (2012), Gems of Geometry, Springer, pp. 28–29, ISBN 9783642309649 .