### IMO Shortlist 2014 problem G3

Kvaliteta:
Avg: 4,0
Težina:
Avg: 7,0
Dodao/la: arhiva
7. svibnja 2017.

Let $\Omega$ and $O$ be the circumcircle and the circumcentre of an acute-angled triangle $ABC$ with $AB > BC$. The angle bisector of $\angle ABC$ intersects $\Omega$ at $M \neq B$. Let $\Gamma$ be the circle with diameter $BM$. The angle bisectors of $\angle AOB$ and $\angle BOC$ intersect $\Gamma$ at points $P$ and $Q$, respectively. The point $R$ is chosen on the line $PQ$ so that $BR = MR$. Prove that $BR \parallel AC$. (Here we always assume that an angle bisector is a ray.)

(Russia)

Izvor: https://www.imo-official.org/problems/IMO2014SL.pdf