MathDB
one of lines DE,DF passes through incenter of ABC, circumcircle related

Source: 2014 All-Ukrainian Correspondence MO of magazine ''In the World of Mathematics'', grades 5-12 p10

April 27, 2021
geometryincentercircumcircleUkraine Correspondence

Problem Statement

In the triangle ABCABC, it is known that AC<ABAC <AB. Let ℓ\ell be tangent to the circumcircle of triangle ABCABC drawn at point AA. A circle with center AA and radius ACAC intersects segment ABAB at point DD, and line ℓ\ell at points EE and FF. Prove that one of the lines DEDE and DFDF passes through the center inscribed circle of triangle ABCABC.
Back to ProblemsView on AoPS