12. Five mark exercise problem II

$ABCD$ is a trapezium in which $AB || DC$ and $P$, $Q$ are points on $AD$ and $BC$ respectively, such that $PQ || DC$ if $PD = 18 \ cm$, $BQ = 35 \ cm$ and $QC = 15 \ cm$, find $AD$.

 

Answer:

 

The length of $AD$ $=$  $cm$