Answer
The missing length is 17.5 units
Work Step by Step
$\frac{x}{3.25}$=$\frac{17.5}{3.25}$ set cross products equal 3.25x=3.25$\times$17.5
3.25x = 56.875
$\frac{3.25x}{3.25}$=$\frac{56.875}{3.25}$ divide by 3.25 both sides
x=$\frac{5687.5}{325}$
x=17.5
The missing length is 17.5 units