The size of the fields can be calculated by diving the fields into triangles. 

Using the Google Earth ruler tool, the sides of each of the triangles in feet can be determined.  

The area of each triangle is then calculated using the formula:

s = (a + b + c) / 2
A = SquareRoot(s * (s - a) * (s - b) * (s - c))

The calculation for each triangle into square feet is given below. With one acre = 43500 square feet, we can calculate acres, and add to get the total size of each field, and the total size of all 3 fields as 9.5 acres.