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Prove that PA*BC = PB*AC = PC*AB

Source: VAIMO 2007, P3

January 3, 2009
geometry unsolvedgeometry

Problem Statement

A point P P in the interior of triangle ABC ABC satisfies \angle BPC \minus{} \angle BAC \equal{} \angle CPA \minus{} \angle CBA \equal{} \angle APB \minus{} \angle ACB. Prove that \bar{PA} \cdot \bar{BC} \equal{} \bar{PB} \cdot \bar{AC} \equal{} \bar{PC} \cdot \bar{AB}.