Because the ratio of the width and the length is 4:3. The length is 4/3 times the width. If you calculate everything in terms of the width you get (4/3)w*1w = (4/3)w^2 = 1323 multiply both sides by 3/4 so it becomes, w^2 = 992.25. The square root of 992.25 is 31.5 so now we know the width of the rectangle. The length is 4/3 times as much as the with so 4/3*31.5 = 42 is the length. (31.5 + 42)*2 = 147
