MathDB
XP/YQ is independent of m

Source: Baltic Way 2017 Problem 12

November 11, 2017
geometryratio

Problem Statement

Line \ell touches circle S1S_1 in the point XX and circle S2S_2 in the point YY. We draw a line mm which is parallel to \ell and intersects S1S_1 in a point PP and S2S_2 in a point QQ. Prove that the ratio XP/YQXP/YQ does not depend on the choice of mm.