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Prove that there is a point M on the circle C

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August 29, 2010
geometry unsolvedgeometry

Problem Statement

Let A1A2A3A4A_1A_2A_3A_4 be a quadrilateral inscribed in a circle CC. Show that there is a point MM on CC such that MA1MA2+MA3MA4=0.MA_1 -MA_2 +MA_3 -MA_4 = 0.