How many acres are in a square mile?

A square mile consists of an area that is one mile long on each side. To convert this measurement into acres, it’s important to know that one mile is equivalent to 5,280 feet. Therefore, the area of a square mile can be calculated by multiplying the length of the sides:

5,280 feet (length) x 5,280 feet (width) = 27,878,400 square feet.

Since each acre is defined as 43,560 square feet, you can find the number of acres in a square mile by dividing the total square feet by the size of an acre:

27,878,400 square feet ÷ 43,560 square feet per acre = 640 acres.

This explains why the correct answer is 640 acres. It is essential to understand the conversions involved when dealing with different units of area, such as square miles and acres, as it helps in various applications, especially in real estate and land surveying.