If a rectangle has a length of 10 and a width of 4, what is its area?

To determine the area of a rectangle, you use the formula:

Area = Length × Width.

In this case, the length of the rectangle is given as 10 and the width is 4. Plugging these values into the formula gives:

Area = 10 × 4 = 40.

Therefore, the area of the rectangle is 40 square units, which corresponds to the answer you selected. This calculation is straightforward, adhering directly to the basic principle of calculating area in geometry. The area provides a measure of the amount of space enclosed within the rectangle.