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BMO Round 2, 2024

Geometry Difficulty 6.0 National Olympiad Prove it United Kingdom

Let ABCABC be an acute-angled triangle with AB>ACAB > AC. Let PP be the intersection of the tangents to the circumcircle of ABCABC at BB and CC. The line through the midpoints of line segments PBPB and PCPC meets lines ABAB and ACAC at XX and YY respectively.

Prove that the quadrilateral AXPYAXPY is cyclic.

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