Let
be a parallelogram. A variable line
through the vertex
intersects the rays
and
at the points
and
, respectively. Let
and
be the
-excenters of the triangles
and
. Show that the angle
is independent of the line
.
%V0
Let $ABCD$ be a parallelogram. A variable line $g$ through the vertex $A$ intersects the rays $BC$ and $DC$ at the points $X$ and $Y$, respectively. Let $K$ and $L$ be the $A$-excenters of the triangles $ABX$ and $ADY$. Show that the angle $\measuredangle KCL$ is independent of the line $g$.
Školjka