1. Perimeter of Rectangles
Lesson 16a

2. Perimeter Perimeter is the distance around the outside of a figure.
The perimeter of a rectangle is derived by adding all four sides. Since the two lengths are equal, and the two widths are equal, then it can be written as P = 2l + 2w.
For squares, the perimeter is found the same way (add all 4 sides). Since all sides are the same, however, you can use the formula P = 4s.

3. P = 2w + 2l P = 2(5) + 2(18) P = 10 + 36 P = 46 cm Example 18 cm 5 cm
Perimeter results in regular units, not square units.
P =
P = 46 cm

4. Practice Time