Donna,

(1) Do you mean square footage, or perimeter, or what?
(2) The area, perimeter, etc. of a freeform pool cannot be determined form length and width data.

Having looked at a few ads on the Web I would say that you would not be far off at 75% the area of a rectangular pool of the same length and width and approximately equal perimeter. So say 190 square feet, with a 64 square foot perimeter - roughly!

If you have a particular pool in mind, if you have an overhead view (or oblique view from a longish distance and not too low an angle) you can copy it onto graph paper and count squares for a more exact figure.

Good Hunting!
RD