Explain why is the area of a rectangle is: Area= l x w?

If you imagine that a rectangle is made up of a bunch of little squares that are 1 unit x 1unit, the total area is the number of those little squares. If you count the number it will amount to the same as the number of squares along one side multiplied by the number down the other side.

Try it!

You want to find the space inside the rectangle; therefore, you multiply the measurement of the length (l) times the measurement of the width (w) to arrive @ the area. The space around the rectangle is called the perimeter, and, in order to find this answer, you multiply twice the measurement of the length + multiply twice the measurement of the width (i.e. P = 2L + 2W). Simple geometry.