Area and perimeter

We were reviewing about perimeter and area in class. Finding the perimeter of a polygon you would have to measure all the sides and add all the measurments up. For finding the area of a polygon you would only have to measure the length and width after that you multiply lenghth times width. So for perimeter you have to measure all the sides and add the measurments up and for area you have to measure lenghth and the width and mutiply the measurments.