Problem 655: Archimedes' Book of Lemmas: Proposition 15 - Circle, Regular Pentagon, Radius

Online Geometry

Let AB be the diameter of a circle, BC a side of an inscribed regular pentagon, D the midpoint of the arc BC. AB and CD meet in E; AD and BC meet in F. If FG is perpendicular to AB, then EG is equal to the radius of circle.


Archimedes' Book of Lemmas: Proposition 15: Circle, Regular Pentagon

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