Question 44
Be an isosceles trapezoid with $AD \gt BC$ $ABCD$. Let $X$ be the intersection of the angle bisectors of $\angle BAC$ and $BC$. Let $E$ be the intersection of $DB$ with parallels to the angular bisector of $\angle CBD$ by $X$ and be $F$ the Intersection of $DC$ with parallels to the angular bisector of $\angle DCB$ by $X$. Show that $AEFD$ is a quadrangle of tendon.