Four Visual Proofs of a Theorem about a Regular Nonagon

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This Demonstration shows four visual proofs that , where
,
, and
are the lengths of a side, the shortest diagonal, and the longest diagonal, respectively, of a regular nonagon. The interior angle of the regular nonagon is
, so that angle 451 equals
.
Contributed by: Izidor Hafner (January 2016)
Open content licensed under CC BY-NC-SA
Snapshots
Details
Reference
[1] Š. Arslanagić, Matematička čitanka 4, Sarajevo, 2012, pp. 63–72.
Permanent Citation
"Four Visual Proofs of a Theorem about a Regular Nonagon"
http://demonstrations.wolfram.com/FourVisualProofsOfATheoremAboutARegularNonagon/
Wolfram Demonstrations Project
Published: January 12 2016