Nonagon

A nonagon or enneagon is a polygon with 9 sides and 9 vertices.

Regular Nonagon

A regular nonagon is a polygon with 9 equal sides and angles.

Angles of the Nonagon

The sum of interior angles of a nonagon = (9 − 2) · 180° = 1,260°

The value of an interior angle of a regular nonagon is: 1,260º : 9 = 140º

The central angle of a regular nonagon measures: 360º : 9 = 40º

Diagonals of the Nonagon

The number of diagonals in a regular nonagon = 9 · (9 − 3) : 2 = 27

Perimeter of a Regular Nonagon

Perimeter = 9 · l

Area of a Regular Nonagon

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