If a rectangular building measures 40 feet by 20 feet, what is its area?

To determine the area of a rectangular building, you can use the formula for area, which is length multiplied by width. In this case, the building measures 40 feet in length and 20 feet in width.

So, you calculate the area as follows:

Area = Length × Width

Area = 40 feet × 20 feet

Area = 800 square feet

Thus, the area of the rectangular building is 800 square feet. This makes the correct choice the one that states 800 sq feet. By applying the area calculation formula correctly, it's easy to see how the answer is derived from the dimensions provided. Calculating area is essential in real estate for understanding the usable space within a property.