Suppose you have enough material for 60 feet of fencing. With this material you want to build the largest rectangular enclosure possible. What are the dimensions of the largest possible enclosure, and what is its area?

Answer 1

I'd build a square enclosure with 15 feet on each side.

Answer 2

Instead of 60 feet, let’s say you have 4x feet of fencing, where x is any number. What, in terms of x, should the dimensions of the largest rectangular enclosure be, whose perimeter is 4x feet? What would the area be?