Learning how to find the perimeter of an object is super easy. There are several different formulas and the video below illustrates two formulas.
The two formulas mentioned in the video are p=4s and p=2l + 2w. These formulas are used when finding the perimeter of a square or rectangle.
To find the perimeter of irregular shapes you must first determine the length of all sides. You can either add all sides together, or locate all the rectangles in the shape (crossing out measurements that do not apply)and then use the p=2l + 2w formula. Finally, add up the totals for each rectangle to find the total for the whole shape.
Practice perimeter for squares and rectangles by playing this fun online game.
Source: softschools.com