what is the distance around the perimeter of ellipse if a= 140.00 ft and b = 30.00 ft

Believe it or not, calculating the perimeter of an ellipse is a very difficult thing to do.....

Here's a very good approximation:

First, calculate "h"   as

h = ( a - b)^2  /  (a + b)^2   =  (140 - 30)^2 / (140 + 30)^2  =  110^2  / 170^2   = 121/289

Then, we can use the this "formula".......the terms in  the brackets comprise the first four terms of an infinite series, but these will do nicely enough for our purposes

P  = pi (a + b) [ 1 + h/4  + h^2/64  + h^3/256]

Substituting in  for a, b and h, we have :

P = about 591.6 ft

You can read more about this, here: https://www.mathsisfun.com/geometry/ellipse-perimeter.html

The infinite sum I referenced can be found under the part "Infinite Series 2"