MathNet 2012 Question 85

$ABCD$ is a trapezoid with $AD\parallel BC$, $K$ is a point on side $AB$, and $L$ is a point on side $CD$. Prove that if $\widehat{BAL}=\widehat{CDK}$, then $\widehat{BLA}$ and $\overline{CKD}$ are equal as well.