MathDB
Circle Incident

Source: 2016 AIME I #15

March 4, 2016
2016 AIME IcirclesAIME

Problem Statement

Circles ω1\omega_1 and ω2\omega_2 intersect at points XX and YY. Line \ell is tangent to ω1\omega_1 and ω2\omega_2 at AA and BB, respectively, with line ABAB closer to point XX than to YY. Circle ω\omega passes through AA and BB intersecting ω1\omega_1 again at DAD \neq A and intersecting ω2\omega_2 again at CBC \neq B. The three points CC, YY, DD are collinear, XC=67XC = 67, XY=47XY = 47, and XD=37XD = 37. Find AB2AB^2.