Hi Riley J
36 is the Perimeter of the Square
Perimeter of the rectangle is 38
Perimeter of a rectangle = 2L + 2W where L is the length and W is the widith
We are given the perimeter so
38 = 2L + 2W
Divide both sides by 2
19 = L + W
So
19 - W = L
We are also given if the Length is decreased by 3 and the width increase by 2 or
L - 3
and
W + 2
The Rectangle becomes a Square
In a Square all the sides are equal so
L - 3 = W + 2 for a square
Since we can make a substitution for L based on the information above from the rectangle we can set up our equations in terms of W and find W.
19 - W = L
Then
(19 - W) - 3 = W + 2
19 - W - 3 = W + 2
16 - W = W + 2
Isolate the variable on one side of the equation
16 = W + W + 2
16 = 2W + 2
Subtract 2 from both sides of the equation
16 - 2 = 2W
14 = 2W
Divide both sides by 2
7 = W
To get the side of the square we need to find the sides of the rectangle
L = 19 - W = 19 - 7 = 12
W = 7
The sides of the square are equal and
L - 3 = W + 2
12 - 3 = 7 + 2
9 = 9
The Perimeter of the Square is 4s = 4(9) = 36
I hope this helps