Rancher Juana wants to build a three-sided rectangular fence near a river, using 180 yards of fencing. Assume that the river runs straight and that Juana need not fence in the side next to the river.
Juana wants to build a fence so that the enclosed area is maximized.
What should be the length of each side running perpendicular to the river?
What should be the length of the side running parallel to the river?
What is the largest total area that can be enclosed?