Finally, subtract your answer by one of the factors...
1,243-1,105
Which will result as 138. Which is also one of the factors you added earlier, that's basically what your looking fro when checking and subtraction and/or addition problem.
A is the closest I got. My answer was 32.665 using thousandth place. I found the perimeter by adding up the lengths. I found all of the lengths by using pathat oran theorem.
