2001 IMO Shortlist Problems/G2
Problem
Consider an acute-angled triangle . Let
be the foot of the altitude of triangle
issuing from the vertex
, and let
be the circumcenter of triangle
. Assume that
. Prove that
.
Solution
See 2001 IMO 1 page. https://artofproblemsolving.com/wiki/index.php/2001_IMO_Problems/Problem_1