MathDB
maximum length in a equilateral, on 2 concentric circles

Source: JBMO Shortlist 2005

January 1, 2018
geometrymaximumconcentricEquilateral Triangle

Problem Statement

Let OO be the center of the concentric circles C1,C2C_1,C_2 of radii 33 and 55 respectively. Let AC1,BC2A\in C_1, B\in C_2 and CC point so that triangle ABCABC is equilateral. Find the maximum length of [OC] [OC] .