Talk:Internal angle

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"The sum of the internal angles of a polygon on a Euclidean plane with n vertices (or equivalently, n sides) is (n − 2)180 degrees."

??? Isn't this true only for CONVEX polygons?

No. --Spoon! 21:14, 23 February 2007 (UTC)

[edit] description of external angle incorrect, and does not match illustration

definition reads, "..an exterior angle (or external angle) is an angle formed by one side of a simple polygon and a line extended from that side."

An angle formed by a side...and a line extended from that side: now, wouldn't that simply be a continuation of a line and thus form NO angle (or a 180° angle)?

I believe this should read, instead: ..."an exterior angle (or external angle) is an angle formed by one side of a simple polygon and a line extended from an adjoining side. 71.209.40.102 (talk) 01:52, 25 January 2008 (UTC)