1.) 2 sides are already gonna be 13 so you already have 26 is you add up both those sides. 13+13=26 2.)Subtract 26 from 46 to get the sum of both the widths added together. 46-26=20 3.)Divide 20 by 2 so that you can get the width on one side of the rectangle. 20 / 2 = 10 4.) The width of the rectangle above is 10 I hope this helps :)