Area and Perimeter

For todays class we were reviewing about perimeter and area. To find the perimeter of a polygon you would have to measure all the sides and add them all up. To find the area of a polygon you would only have to measure the length and width, then you multiply lenghth times width. I know the difference between area and perimeter is, for perimeter you have to measure all the sides and add them up, but for area you would ONLY have to measure lenghth and the width and multiply them.