# Decagon (EntityTopic, 12)

(Difference between revisions)
 Revision as of 22:06, 16 February 2014 (view source)Hayate (Talk | contribs) (polytope explorer integration)← Older edit Revision as of 16:18, 26 March 2017 (view source)Newer edit → Line 8: Line 8: | extra={{STS Matrix| | extra={{STS Matrix| 10 0 10 0 - 1 1}}{{STS Uniform polytope + 1 1}}{{STS Polytope - | schlaefli={10} + | dual=''self-dual'' - | vfigure=[[Digon]], length 1 + | acronym=Dec}}{{STS Uniform polytope - | dual=''Self-dual'' + | schlaefli={10}, t{5} + | dynkin=x10o, x5x + | vfigure=[[Digon]], length √((5+√5)/2) }}}} }}}} - <[#polytope [id -10]]> + 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: + {{Over|5|2}} · √((5+2√5)/2) · ''l''2 + + (<[#polytope [id -10]]> {{Dishapes}} {{Dishapes}}

## Revision as of 16:18, 26 March 2017

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:

52 · √((5+2√5)/2) · l2

(

## Incidence matrix

Dual: Self-dual

 # TXID Type Name Va Ea 0 Va = point ; 1 Ea 2 = digon ; 2 10a 10 10 = decagon ;

## Usage as facets

 Notable Dishapes Flat: triangle • square • pentagon • hexagon • octagon • decagon Curved: circle