Question 22
Let $\Gamma$ be the ex-inscribed circumference to the triangle $ABC$ opposite to the vertex $A$, ie the tangent circumference to $BC$ and ai Extensions of the $AB$ and $AC$ sides on the part of $B$ and $C$. Let $D$ be the center of $\Gamma$ and let $E$ and $F$, respectively, the tangency points of the $\Gamma$ with the extensions of the sides $AB$ and $AC$. Let $J$ be the intersection between segments $BD$ and $EF$. Prove that the angle $\angle CJB$ is straight.