Enneadecagon

From Wikipedia, the free encyclopedia

An enneadecagon.

In geometry, an enneadecagon is a polygon with 19 sides and angles. It is also known as an enneakaidecagon or a nonadecagon. The internal angles of a regular enneadecagon each measure approximately 161.052 degrees, and the area with side length of a is given by

$A = \frac{19}{4}a^2 \cot \frac{\pi}{19} \simeq 28.4652 a^2.$

The radius of the circumcircle of the regular enneadecagon with side length a is $R=\frac{a}{2} \csc \frac {180}{19}$ (angle measure in degrees)

[edit] External links

Enneadecagon at MathWorld

Polygons
Triangle • Quadrilateral • Pentagon •Hexagon • Heptagon • Octagon • Enneagon (Nonagon) • Decagon • Hendecagon • Dodecagon • Triskaidecagon • Pentadecagon • Hexadecagon • Heptadecagon • Enneadecagon • Icosagon • Chiliagon • Myriagon