How do you find the area of a rectangle with length 10 cm and width 4 cm?

To find the area of a rectangle, you multiply its length by its width. In this case, the length is 10 cm and the width is 4 cm. Therefore, the area can be calculated as follows:

Area = Length × Width

Area = 10 cm × 4 cm = 40 cm²

This method is fundamental in geometry and applies universally to all rectangles. The chosen approach of multiplication accurately represents the two-dimensional space occupied by the rectangle.

The other options do not apply to the formula for the area. Adding the length and width only provides a perimeter-like figure without considering area. Subtracting is not relevant to determining area, and dividing would not provide a meaningful value in this context either. Thus, the multiplication method is indeed the correct one to use for calculating the area of a rectangle.