Enneadecagon

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Regular enneadecagon
Enneadecagon.svg
A regular enneadecagon
TypeRegular polygon
Edges and vertices19
Schläfli symbol{19}
Coxeter diagramCDel node 1.pngCDel 19.pngCDel node.png
Symmetry groupDihedral (D19), order 2×19
Internal angle (degrees)≈161.052°
Dual polygonSelf
PropertiesConvex, cyclic, equilateral, isogonal, isotoxal

A enneadecagon or 19-gon is a shape with 19 sides and 19 corners.[1] It is also known as an enneakaidecagon or a nonadecagon.[2]

Regular enneadecagon[change | change source]

All sides of a regular enneadecagon are the same length. Each corner is ≈161.052°. All corners added together equal 6840°.

The radius of the circumcircle of the regular enneadecagon with side length t is (angle in degrees). The area, where t is the edge length, is

References[change | change source]

  1. Borges, Samantha; Morgan, Matthew (2012), Children's Miscellany: Useless Information That's Essential to Know, Chronicle Books, p. 110, ISBN 9781452119731.
  2. McKinney, Sueanne; Hinton, KaaVonia (2010), Mathematics in the K-8 Classroom and Library, ABC-CLIO, p. 67, ISBN 9781586835224.

Other websites[change | change source]