To find the perimeter, you add all of the side lengths together. This would make the equation 28+28+n+n. You already know the perimeter and are trying to find n. Your new equation is 28+28+n+n=86
You would then combine the like terms and get
56+2n=86
Then you would subtract 56 from both sides and get
2n=30
Finally, you want to divide both sides by 2 in order to get n alone. 30/2 is 15. Therefore,
