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Isogonal conjugate on (BIC)

Source: Kvant Magazine No. 5-6 2024 M2794

August 25, 2024
geometry

Problem Statement

The points PP and QQ lie inside the circle ω\omega. The perpendicular bisector to the segment PQPQ intersects ω\omega at points AA and DD. A circle centered on DD passing through PP and QQ intersects ω\omega at points BB and CC. The segment PQPQ lies inside the triangle ABCABC. Prove that ACP=BCQ\angle ACP = \angle BCQ. Proposed by A. Zaslavsky