a.A rectangular pen is built with one side against a barn. If 400 m of fencing are used for the other three sides ofthe pen, what dimensions maximize the area of the pen? I). A rancher plans to make four identical and adjacent rectangular pens against a barn, each with an area of 25 m2 (see gure}. What are the dimensions of each pen that minimize the amount of fence that must be used? f ..... ' a. To maximize the area of the pen, the sides perpendicular to the barn should be m long and the side parallel to the barn should be m long. (Type exact answers, using radicals as needed} b. To minimize the amount of fence that must be used, each ofthe sides perpendicular to the barn should be m long and each of the sides parallel to the barn should be m long. (Type exact answers, using radicals as needed}