The rectangle with the maximum area for a given perimeter is a square. The perimeter of a square is 4 times the side length, so the side length of the square area will be ...
(272 ft)/4 = 68 ft
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<em>More formally ...</em>
You can let x represent the length of one side. Then the length of the other side for the given perimeter will be 136 -x, and the area will be the product ...
area = x(136 -x)
The area function is a quadratic with zeros at x=0 and x=136. The vertex (maximum area) will be at the value of x that is on the line of symmetry between these points, at their midpoint: x = (0 +136)/2 = 68. This value of x makes the rectangle a square.
