fixed length for AK, common ext. tangent of incircles of ABD, ACD
Source: TOT 416 1994 Spring A S4 - Tournament of Towns
June 12, 2024
geometryfixed
Problem Statement
A point is placed on the side of the triangle . Circles are inscribed in the triangles and , their common exterior tangent line (other than ) intersects at the point . Prove that the length of does not depend on the position of . (An exterior tangent of two circles is one which is tangent to both circles but does not pass between them.) (I Sharygin)