MathDB
Igo 2021 intermediate p4

Source: Intermediate p4

December 30, 2021
geometry

Problem Statement

Let ABCABC be a scalene acute-angled triangle with its incenter II and circumcircle Γ\Gamma. Line AIAI intersects Γ\Gamma for the second time at MM. Let NN be the midpoint of BCBC and TT be the point on Γ\Gamma such that INMTIN \perp MT. Finally, let PP and QQ be the intersection points of TBTB and TCTC, respectively, with the line perpendicular to AIAI at II. Show that PB=CQPB = CQ. Proposed by Patrik Bak - Slovakia