A javalina rancher wants to enclose a rectangular area and then divide it into five pens with fencing parallel to one side of the rectangle (see the figure below). There are 510 feet of fencing available to complete the job. What is the largest possible total area of the five pens?

$$\begin{array}{|c|c|c|c|c|} \hline & & & & \\ \hline \end{array}$$

Largest area = (include units)