A rectangle has 4 sides: 2 widths and 2 lengths. We know the two lengths and the two widths are the same (otherwise it wouldn't be a rectangle!).
If the width is 5, then we add another 5 for second width. That's 10 total.
32 - 10 = 22. This is the total of both of the lengths. As we mentioned before, we know each length is the same, so we can cut this in half.
Each length is 11.
11 + 11 + 5 + 5 = 32.
Each length is 11. Each width is 5.