Y by
In a triangle
,
is the incenter, and
is the center of the tangent circle for the side
and the extensions of the other sides. A point
is chosen on the arc
of the circumcircle of
, so that
is a half of
.
is the midpoint of the arc
of the circumcircle of
. Prove that the points
lie on one straight line.
(O. Pyaive)













(O. Pyaive)