Lorenzo wants to build a rectangular enclosure for his animals. One side of the pen will be
against the barn, so he needs no fence on that side. The other three sides will be enclosed
with wire fencing. If Lorenzo has 700 feet of fencing, you can find the dimensions that
maximize the area of the enclosure.
a) Let w be the width of the enclosure (perpendicular to the barn) and let I be the length of
the enclosure (parallel to the barn). Write an function for the area A of the enclosure in terms
of w. (HINT first write two equations with w and I and A. Solve for l in one equation and
substitute for I in the other).
b) What width w would maximize the area?

c) What is the maximum area?