MathDB
a line passing through the incenter

Source: bmo 1986

April 23, 2007
geometryincentercircumcirclegeometry proposed

Problem Statement

A line passing through the incenter II of the triangle ABCABC intersect its incircle at DD and EE and its circumcircle at FF and GG, in such a way that the point DD lies between II and FF. Prove that: DFEGr2DF \cdot EG \geq r^{2}.