The area is 96ft.
We know that the perimeter includes four sides. Divide the 40 by 4. You will get 10. Four sides of ten would get you a perimeter of 40. Now take two tens, one for the length and the width. Add 2 to one side and subtract 2 from the other. This will get a length of 12 and a width of 8. Than multiply the 12 and 8 to get the area. You will get 96.