Manuel decides to build a fence to enclose an area for his dogs to play. The area is to be rectangular in shape. If he has 80 feet of fencing, find the dimensions of the rectangle that will give the dogs the maximum area in which to play. Only 3 sides need to be fenced, because his house is to be one border of the rectangle.

Step-by-step explanation:

We know that Manuel decides to build a fence to enclose an area for his dogs to play. The area is to be rectangular in shape.  We know that  only 3 sides need to be fenced, because his house is to be one border of the rectangle.

We conclude that the the maximum area  is:

So the two shorter sides will be 20 feet each, the longer side will be 40 feet.