Decagon (EntityTopic, 12)
From Hi.gher. Space
A decagon is a polygon with 10 sides. It is the truncated pentagon.
Coordinates
The coordinates of a regular decagon are:
(0, ±2φ)
(±1, ±√(3+4φ)
(±(1+φ), ±√(2+φ)
Equations
- The area of a regular decagon is:
5∕2 · √((5+2√5)/2) · l2
(Incidence matrix
Usage as facets
- prism: 2× 1-facets of a decagonal prism
- 12× 1-facets of a truncated dodecahedron
- 12× 1-facets of a rhodopantohedron
- 1× 1-facets of a pentagonal cupola
- 24× 2-facets of a castellated rhodopantohedral prism (named 5 end)
Notable Dishapes | |
Flat: | triangle • square • pentagon • hexagon • octagon • decagon |
Curved: | circle |