MathDB
Romania TST 2016 Day 1 P1

Source: Romania TST 2016 Day 1 P1

November 1, 2017
geometry

Problem Statement

Two circles, ω1\omega_1 and ω2\omega_2, centered at O1O_1 and O2O_2, respectively, meet at points AA and BB. A line through BB meet ω1\omega_1 again at CC, and ω2\omega_2 again at DD. The tangents to ω1\omega_1 and ω2\omega_2 at CC and DD, respectively, meet at EE, and the line AEAE meets the circle ω\omega through A,O1,O2A, O_1,O_2 again at FF. Prove that the length of the segment EFEF is equal to the diameter of ω\omega.