I assume that this 'something' has a rectangular shape. If its width is 5m, than the length of two sides is 2 * 5 = 10m. Now if the perimeter is 22 square meters, then the lenght of another two sides is 12 / 2 = 6.
12 because 22 (the perimeter) - 10 (lenght of the 2 sides) = 12 (length of another 2 sides).
