If you would like to know what is the measure of the adjacent side, you can calculate this using the following steps:
an area = length * width
3 1/8 square feet = 2 1/2 feet * x
3 1/8 = 2 1/2 * x
25/8 = 5/2 * x
x = 25/8 * 2/5
x = 5/4 = 1 1/4 feet
The correct result would be 1 1/4 feet.
