olymmath

ISL 2020 G2

    Let ABCDA B C D be a convex quadrilateral. Suppose that PP is a point in the interior of ABCDA B C D such that ∠PAD:∠PBA:∠DPA=1:2:3=∠CBP:∠BAP:∠BPC.\angle P A D: \angle P B A: \angle D P A=1: 2: 3=\angle C B P: \angle B A P: \angle B P C . The internal bisectors of angles ADPA D P and PCBP C B meet at a point QQ inside the triangle ABPA B P. Prove that AQ=BQA Q=B Q. (Poland)

    Dataset text NuminaMath olympiads. Quoted with source.

    Official text: IMO 2020 Shortlist booklet, page 10.

    Solutions

    Official solution Solution 1 by the IMO Problem Selection Committee

    The terms of the source let olymmath link to this solution but not copy it. Read the solution (IMO official site).

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