</font><font color="blue" class="small">( Hmmmm I guess what I should have asked is when someone says they have a pond a certain size in acreage, how did they come to this conclusion? Can you step it off, the perimeter? )</font>
Stepping off the perimiter is not accurate, unless the pond is a (near) perfect circle. The largest area that can be enclosed by a given perimeter length is a perfect circle. If you alter the shape from a perfect circle, the enclosed area goes down, until you reach near zero area (imagine an area 100 meters by 1 millimeter).
Dave