Answer
The longest side of $WXYZ=11.2$.
Work Step by Step
Since quadrilateral $MNPQ\sim WXYZ$, corresponding sides are proportional.
$\frac{PQ}{YZ}=\frac{5}{7}$
The ratio of the sides is 5:7. Therefore...
$\frac{5}{7}=\frac{8}{x}$ ...with $x$ representing the unknown side length.
Cross multiply...
$5x=56$
Divide by 5...
$x=11.2$
The longest side of $WXYZ=11.2$.
