Well, its kind of obivious that 2x + 4 stands out, but I think you are asking why. Whereas all other lines shown are vertical or horizontal, 2x+4 is diagonal.
The area of a parallelogram can be found in the same way as that of a rectangle, so base x height. To find the base we have to do area ÷ height or 18 1/3 ÷ 3 1/3= 5.5 feet
