Enneadecagon

Enneadecagon
(OFF file)
Rank	2
Type	Regular
Space	Spherical
Notation
Coxeter diagram	x19o
Schläfli symbol	{19}
Elements
Edges	19
Vertices	19
Vertex figure	Dyad, length 2cos(π/19)
Measures (edge length 1)
Circumradius	$\frac{1}{2\sin\frac{\pi}{19}} ≈ 3.03777$
Inradius	$\frac{1}{2\tan\frac{\pi}{19}} ≈ 2.99634$
Area	$\frac{19}{4\tan\frac{\pi}{19}} ≈ 28.46519$
Angle	$\frac{17\pi}{19} ≈ 161.05263°$
Central density	1
Number of pieces	19
Level of complexity	1
Related polytopes
Army	{19}
Dual	Enneadecagon
Conjugate	8 total
Abstract properties
Euler characteristic	0
Topological properties
Orientable	Yes
Properties
Symmetry	I2(19), order 38
Convex	Yes
Nature	Tame

The enneadecagon is a polygon with 19 sides. A regular enneadecagon has equal sides and equal angles.

A circle with radius 3 centered at the center of an enneadecagon intersects its sides. This is related to the fact that 19/3 ≈ 2π.

Stellations

• 2-enneadecagram
• 3-enneadecagram
• 4-enneadecagram
• 5-enneadecagram
• 6-enneadecagram
• 7-enneadecagram
• 8-enneadecagram
• 9-enneadecagram

External links

• Bowers, Jonathan. "Regular Polygons and Other Two Dimensional Shapes".

• Wikipedia Contributors. "Enneadecagon".