MathDB
Find the length as a function of r_1 and r_2

Source:

September 22, 2010
geometrylengthscirclesLocus problemsIMO Shortlist

Problem Statement

We are given two mutually tangent circles in the plane, with radii r1,r2r_1, r_2. A line intersects these circles in four points, determining three segments of equal length. Find this length as a function of r1r_1 and r2r_2 and the condition for the solvability of the problem.