Question 88
The quadrilateral $ABCD$ has $AD = DC = CB \lt AB$ and $AB \parallel CD$. Points $E$ and $F$ lie on the sides $CD$ and $BC$ such that $\widehat{ADE} = \widehat{AEF}$. Prove that:
a. $4CF \leq CB$.
b. If $4CF = CB$, then $AE$ is the angle bisector of $\widehat{DAF}$.
a. $4CF \leq CB$.
b. If $4CF = CB$, then $AE$ is the angle bisector of $\widehat{DAF}$.