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< BAC <=150^o if max (BX,CX) <= AX <= BC

Source: 2015 Baltic Way Shortlist G7 BW https://artofproblemsolving.com/community/c2641329_baltic_way_shortlist__geometry

November 23, 2021
anglesgeometric inequalitygeometry

Problem Statement

Suppose that A,B,CA, B, C, and XX are any four distinct points in the plane with max(BX,CX)AXBC.\max \,(BX,CX) \le AX \le BC. Prove that BAC150o\angle BAC \le 150^o.