MathDB
Incentre with perpendicularity

Source: Latvia BW TST 2021 P11

September 26, 2021
geometryincenterperpendicular bisector

Problem Statement

Incircle of ABC\triangle ABC has centre II and touches sides AC,ABAC, AB at E,FE,F, respectively. The perpendicular bisector of segment AIAI intersects side ACAC at PP. On side ABAB a point QQ is chosen so that QIFPQI \perp FP. Prove that EQABEQ \perp AB.