You can
put this solution on YOUR website!The Perimeter is:

-------------------
The Area is:

--------------------
First of all, when the coefficient of the
squared term is negative, then there is a maximum
and not a minimum.
When the equation is in the form

, the max or min is
always at

, or, in this case,

and I know that

The largest area that the farmer can enclose
is

= 62,500 ft2
-------------------------------
I can prove this by changing the dimensions
slightly, but still keeping the same Perimeter

= 62,499 ft2

= 62,496 ft2 ( even less )