Units of Measurement
This is for units of measuremnent.
1 acre = 43,560 square feet = A square with side length of 209 feet = "75% of an American football field or 16 tennis courts in a 4x4 formation. If that doesn't help, consider a car park containing 150 cars parked in a square." https://www.thecalculatorsite.com/articles/units/how-big-is-an-acre.php . One square mile is equal to 640 acres.