Question: how do you calculate length and width from total square footage?
Answer: Width. Divide the area by the length if you are given these two figures but not the width. For example, if a rectangle has an area of 20 square feet and a length of 10 feet, divide 20 by 10 to get a width of 2 feet. Multiply the length times 2 and subtract this figure from the perimeter, if you're given these values.