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A polygon of nine sides, having an internal angle sum of 1260 degrees.
Proper name: enneagon

For a regular nonagon with sides of length x,

Area = x26.182

If each corner of the nonagon is connected to the 2 furthest corners with straight lines to form a nonagram, 37 separate areas are formed: 36 triangles and 1 nonagon.

Non"a*gon (?), n. [L. nonus ninth + Gr. angle.] Math.

A figure or polygon having nine sides and nine angles.


© Webster 1913.

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