===============================================
Work Shown:
(1 inch)/(40 miles) = (5 inches)/(x miles)
1/40 = 5/x
1*x = 40*5 .... cross multiply
x = 200 miles
------------
We could also look at it like this:
1 inch = 40 miles
5*(1 inch) = 5*(40 miles) .... multiply both sides by 5
5 inches = 200 miles