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There exists a point M depending on C1, C2 [Spain 2000]

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February 3, 2011
geometrygeometric transformationreflectionperpendicular bisectorgeometry unsolved

Problem Statement

Two circles C1C_1 and C2C_2 with the respective radii r1r_1 and r2r_2 intersect in AA and B.B. A variable line rr through BB meets C1C_1 and C2C_2 again at PrP_r and QrQ_r respectively. Prove that there exists a point M,M, depending only on C1C_1 and C2,C_2, such that the perpendicular bisector of each segment PrQrP_rQ_r passes through M.M.