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Source: Canada Repechage 2022/7 CMOQR

March 19, 2022
geometryCanadarepechage

Problem Statement

Let ABCABC be a triangle with AB<AC|AB| < |AC|, where | · | denotes length. Suppose D,E,FD, E, F are points on side BCBC such that DD is the foot of the perpendicular on BCBC from AA, AEAE is the angle bisector of BAC\angle BAC, and FF is the midpoint of BCBC. Further suppose that BAD=DAE=EAF=FAC\angle BAD = \angle DAE = \angle EAF = \angle FAC. Determine all possible values of ABC\angle ABC.