Maths Olympiad Prep

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, 2024

Geometry Difficulty 7.0 National Olympiad, round 2 Prove it Hungary

Convex quadrilateral ABCDABCD is circumscribed about circle ω\omega. A tangent to ω\omega parallel to diagonal ACAC meets diagonal BDBD at point PP outside of ω\omega. The second tangent from PP to ω\omega touches ω\omega at point TT. Prove that ω\omega and the circumcircle of triangle ATCATC are tangent.

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