similar triangles
Source: Vietnam NMO 1995, Problem 3
September 7, 2008
geometry proposedgeometry
Problem Statement
Let a non-equilateral triangle and are its altitudes. On the rays respectively, let such that \frac {AA'}{AD} \equal{} \frac {BB'}{BE} \equal{} \frac {CC'}{CF} \equal{} k. Find all values of such that for any non-triangle