italy TST
Source: Italian IMO Team Selection Test 1996
May 5, 2017
geometry
Problem Statement
3.Let ABCD be a parallelogram with side AB longer than AD and acute angle
. The bisector of ∠DAB meets side CD at L and line BC at K. If O is
the circumcenter of triangle LCK, prove that the points B,C,O,D lie on a circle.