Difference between revisions of "Ptolemy's Inequality"

m (Ptolemy inequality moved to Ptolemy's Inequality: fixed name)
m (A link to 'cyclic quadrilateral' in case someone doesn't know what it is.)
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Ptolemy's inequality for a convex quadrilateral ABCD states that AB·CD + BC·DA ≥ AC·BD with equality iff ABCD is a cyclic quadrilateral.
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Ptolemy's inequality for a convex quadrilateral ABCD states that AB·CD + BC·DA ≥ AC·BD with equality iff ABCD is a [[cyclic quadrilateral]].

Revision as of 15:52, 20 June 2006

Ptolemy's inequality for a convex quadrilateral ABCD states that AB·CD + BC·DA ≥ AC·BD with equality iff ABCD is a cyclic quadrilateral.

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