Ontario Mathematics Proficiency Practice Test

To calculate the area of a rectangle, you use the formula that involves multiplying the length by the width. This is because the area represents the total space enclosed within the rectangle.

Imagine a rectangle with a certain length and width. By multiplying these two dimensions, you can visualize that you're essentially counting how many unit squares (1 unit by 1 unit) can fit inside the rectangle. Each unit square contributes to the total area, so multiplying length and width gives a precise measurement of the entire space.

The other methods listed do not give the correct area of a rectangle. Adding length and width would only provide a perimeter-related concept but does not translate to area. Dividing length by width would result in a ratio, not an area measurement, and multiplying width by height relates to the area of a parallelogram or rectangle in a different context but does not apply directly here since the height is not a standard term for rectangles where only length and width are considered. Thus, length times width is the accurate calculation for the area of a rectangle.