Answer:
8 ft
Step-by-step explanation:
You have a rectilinear plane figure and want to know one side length when all the others are given.
Sums
The sum of left-side vertical dimensions is equal to the sum of right-side vertical dimensions:
13 ft = ? ft + 5 ft
(13 -5) ft = ? ft . . . . . . . subtract 5 ft
8 ft = ? ft . . . . . . . . . . simplify
