Find the area of the adjoining figure In the adjoining figure, $ABCD$ is a trapezium in which $AB||DC$; $AB=7$ $cm$; $AD=BC=5$ $cm$ and distance between $AB$ and $DC$ is $4$ $cm$. Find the length of $DC$ and hence, find the area of trap.$ABCD$. What I did try is in the attached picture. Please do find it.!enter image description here

$DL^2 = AD^2 - AL^2$

=> $DL^2 = 9$

=> $DL = 3$

the same way $MC=3$

$LM = AB = 7$

=> $DC = DL + LM + MC$

=> $DC = 3 + 7+ 3$

=> $DC = 13$