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center or rectanglie lies on MN - All-Russian MO 1997 Regional (R4) 10.2

Source:

September 24, 2024
geometryrectanglecollinear

Problem Statement

Circles S1S_1 and S2S_2 intersect at points MM and NN. Prove that if vertices AA and C C of some rectangle ABCDABCD lie on the circle S1S_1, and the vertices BB and DD lie on the circle S2S_2, then the point of intersection of its diagonals lies on the line MNMN.