445 + 210 + 525 = 1,180
500 + 85x = 1,180
-500 -500
85x = 680
/85 /85
x = 8
Step One
Find AM
Formula
AM = MN - AN
Givens
MN = 67.2
AN = 32
Solution
AM - 67,2 - 32
AM = 35.2
Step Two
Set up a solution
67.2/35.2 = 81.9/x Cross Muliply
67.2 * x = 81.9 * 35.2 Combine the right
67.2 * x = 2882.88 Divide by 67.2
x = 2882.88/67.2
x = 42.9 Answer
This is the "commutative property of addition." The order in which you add numbers together doesn't matter, and doesn't change your final results.
