The largest area would be a square shape.
A square has 4 equal sides:
1800/4 = 450
Now because the street side doesn't have fencing, add that side length to one side of the fencing:
450 +450 = 900
Now the fence would have two widths of 450 feet and one length of 900 feet.
Area = length x width = 450 x 900 = 405,000 square feet.
