The acre(ac) is a unit of land area used in the imperial and US customary systems while a square mile(sq. mi) is a unit of area measurement equal to a square measuring one mile on each side.
Formula to convert ac to sq. mi..
To convert acres to sq. mi, we need to know the conversion ratio which we get from how they relate to each other.
We are told that 1 sq. mi is equal to 640 acres.
Therefore, to convert acres to sq. mi, we divide the acres value by 640.
Area in sq. mi = Area in Acres ÷ 640
Convert 500 acres to square miles.
= 500 ÷ 640
= 0.78 square miles.