A square garden plot measures 125 square feet. A second garden garden measures 405 square feet. How many more feet of fence will the second garden plot require over that required for the first garden plot? I really have no idea how to do this. Solution Length of the Fence in First case  = 125 = 11.18 Lenght in second Case = 405 = 20.12 Therefore More Fence needed = 4*(20.12-11.18) = 35.76 ft .