If the area was completely square in shape, each side would be just around 1.75 miles long.
"square miles" is created mostly using rectangular shaped areas. It is created by multiplying the length by the width.
For instance, if something is square, and 1 yard on each side, you would multiply 1yd x 1yd which would equal 1 sq yard. Since 'yard' was multiplied twice, it's 'squared' - basically meaning it has an exponent.
So to revert a "square miles" to calculate the length of each side, simply find the square root of the number. The square root of 3.1 is around 1.75
Maybe I misinterpreted what you were asking for. 1926.4 Acres if that's what you are looking for.
The area is 21*31 = 651 square feet.
The area of Bianco is 31 square kilometers.
The area of Zvezdara is 31 square kilometers.
The area of Lumezzane is 31 square kilometers.
The area of Tratalias is 31 square kilometers.
The area of Táliga is 31 square kilometers.
The area of Letino is 31 square kilometers.
The area of Valsinni is 31 square kilometers.
The area of Gambara is 31 square kilometers.
The area of Bádenas is 31 square kilometers.
The area of Alcanadre is 31 square kilometers.
The area of Conflenti is 31 square kilometers.