Enneadecagon

From Free net encyclopedia

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

<math>A = \frac{19}{4}a^2 \cot \frac{\pi}{19} \simeq 28.4652 a^2.</math>

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

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