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PQ tangent to circumcircle of ABC

Source: Mediterranean Mathematical Olympiad 2022 P4 MMC

September 21, 2022
geometrytangent

Problem Statement

The triangle ABCABC is inscribed in a circle γ\gamma of center OO, with AB<ACAB < AC . A point DD on the angle bisector of BAC\angle BAC and a point EE on segment BCBC satisfy OEOE is parallel to ADAD and DEBCDE \perp BC. Point KK lies on the extension line of EBEB such that EA=EKEA = EK. A circle pass through points A,K,DA,K,D meets the extension line of BCBC at point PP, and meets the circle of center OO at point QAQ\ne A. Prove that the line PQPQ is tangent to the circle γ\gamma.