MathDB
Where is the largest segment

Source: Kvant Magazine No. 9 2020 M2621

March 9, 2023
geometryexcircleKvant

Problem Statement

Consider a triangle ABCABC in which AB<BC<CAAB<BC<CA. The excircles touch the sides BC,CA,BC, CA, and ABAB at points A1,B1A_1, B_1 and C1C_1 respectively. A circle is drawn through the points A1,B1A_1, B_1 and C1C_1 which intersects the sides BC,CABC, CA and ABAB for the second time at the points A2,B2A_2, B_2 and C2C_2 respectively. On which side of the triangle can lie the largest of the segments A1A2,B1B2A_1A_2, B_1B_2 and C1C2C_1C_2?
Proposed by I. Weinstein