http://demonstrations.wolfram.com/ConstructingARegularPentagonWithRulerAndCompass/
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This shows a step-by-step ruler and compass construction of a regular pentagon. The construction is due to H. W. Richmond, "A Construction for a Regular Polygon of Seventeen Sides," Quart. J. Pure Appl. Math., 26, 1893 pp. 206-207.
Contributed by: Oleksandr Pavlyk
