IMO Shortlist 2005 problem G6
Avg:
Avg:
Let
be a triangle, and
the midpoint of its side
. Let
be the incircle of triangle
. The median
of triangle
intersects the incircle
at two points
and
. Let the lines passing through
and
, parallel to
, intersect the incircle
again in two points
and
. Let the lines
and
intersect
again at the points
and
. Prove that
.






















Izvor: Međunarodna matematička olimpijada, shortlist 2005