MathDB
MN = AE +AF, 2 intersecting circles

Source: All-Russian MO 1995 Regional (R4) 11.7

August 26, 2024
geometryequal segments

Problem Statement

Circles S1S_1 and S2S_2 with centers O1O_1 and O2O_2 respectively intersect at AA and BB. Ray O1BO_1B meets S2S_2 again at FF, and ray O2BO_2B meets S1 S_1 again at EE. The line through BB parallel to EF EF intersects S1S_1 and S2S_2 again at MM and NN, respectively. Prove that MN=AE+AFMN = AE +AF.