Which unit equals 43,560 square feet?

• A. One acre
• B. One square mile
• C. One township
• D. One square foot

Answer: (A)

Area for land is commonly measured in acres, with one acre equaling 43,560 square feet. This comes from the historical definition: an acre is 160 square rods, and a rod is 16.5 feet long. A square rod is 16.5 by 16.5 feet, which is 272.25 square feet; multiplying by 160 gives 43,560 square feet. For context, a square mile is 5,280 feet on each side, which is 27,878,400 square feet (640 acres). A township is 6 miles by 6 miles, or 36 square miles (about 23,040 acres). A single square foot is only 1 square foot. So the unit that equals 43,560 square feet is an acre.