2n + 2(n+0.6) = p
perimeter is all 4 sides added together in length. Since we understand one of the sides as n, we can multiply by 2 to represent both of those sides. We then understand the other side as n+0.6. We can multiply that by 2 to represent the other two sides.
Adding the representation of 2 sides to the representation of 2 sides will equal the perimeter if we ever discover what n is numerically.
