Troy,
I am going to assume that your oval is an ellipse.
Unfortunately there is no simple expression for the perimeter of an ellipse, but there is an approximation that you can find in a solution to an earlier problem. To use this approximation you need the lengths of the semiaxes a and b of the ellipse. In your situation a = 19 ft and b = 9 ft. The approximation is to the perimeter is
Penny
