15. Four mark exercise problems VII

In a parallelogram $PQRS$ (see the diagram) $PM$ and $PN$ are the heights corresponding to the sides $QR$ and $RS$ respectively. If the area of the parallelogram is $900 \ sq. \ cm$ and the length of $PM$ and $PN$ are $20 \ cm$ and $36 \ cm$, respectively, find the length of the sides $QR$ and $SR$.

 

 

Answer:

 

$QR =$  $cm$

 

$SR =$  $cm$