Let the lenght perpendicular to street = x
Means lenght two sides will be x and x
Another side of retangle will be = 256 - 2x
Area of rectangle will be= A = x * (256-2x) = 256 x - 2 x^2
For maximum area, dA/dx = 0
d/dx (256 x - 2 x^2) = 0
256 - 4 x = 0
4 x = 256
x = 64 feet
Means one side is 64 feet
Another side will be = 256 - 2 * 64 = 128
Now we have two sides of rectangle 64 and 128
Area = 128 * 64 = 8192 square feet : Answer
Hope it will help :)
