Question

Why do you have to use the formula a=l×w

Answer 1

Because the bottom or length multipled by the width gets you the area

Answer 2

Answer:

This formula corresponds to find the area of a rectangle/square.  You multiply one side by the other to get the area.

Example:  The sides of a rectangle are 6 in and 14 in.  Find the area.

A = l * w

A = 6 * 14

A = 84