Cyclic polygon

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Revision as of 14:57, 23 November 2008 by imported>Richard Pinch (sp)
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In plane geometry, a cyclic polygon is a polygon whose vertices all lie on one circle. The centre of the circle is the circumcentre of the polygon,

Every triangle is cyclic, since any three (non-collinear) points lie on a unique circle.

A cyclic quadrilateral is a quadrilateral whose four vertices are concyclic. A quadrilateral is cyclic if and only if pairs of opposite angles are supplementary (add up to 180°, π radians).