Answer:
l = 2 1/2 ft
Explanation:
The formula for A is l*w for a rectangular length
A= lw
Putting in what we know
8 1/2 = l * 3 2/5
I will change mixed numbers to improper fractions
8 1/2 = (2*8+1)/2 = 17/2
3 2/5 = (5*3+2)/5 = 17/5
17/2 = l*17/5
Multiply both sides by 5/17 to isolate l
5/17* 17/2 = l* 17/5 * 5/17
5/2 = l
Changing this back to a mixed number
2 1/2 = l