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iran tst 2018 geometry

Source: Iranian TST 2018, second exam day 2, problem 5

April 17, 2018
geometry

Problem Statement

Let ω\omega be the circumcircle of isosceles triangle ABCABC (AB=ACAB=AC). Points PP and QQ lie on ω\omega and BCBC respectively such that AP=AQAP=AQ .APAP and BCBC intersect at RR. Prove that the tangents from BB and CC to the incircle of AQR\triangle AQR (different from BCBC) are concurrent on ω\omega.
Proposed by Ali Zamani, Hooman Fattahi