1. Holt CA Course 1 10-1 Perimeter Warm Up 1. What figure has four equal sides and four right angles? 2. What figure has eight sides? 3. What figure has five sides? square octagon pentagon

2. Holt CA Course 1 10-1 Perimeter AF3.1 Use variables in expressions describing geometric quantities (e.g., P = 2w + 2l, A = bh, C =  d–the formulas for the perimeter of a rectangle, the area of a triangle, and the circumference of a circle, respectively). Also covered: AF1.1, AF1.2, AF3.2 California Standards 1212

3. Holt CA Course 1 10-1 Perimeter Vocabulary perimeter

4. Holt CA Course 1 10-1 Perimeter perimeter the sum of the lengths of a polygon’s sides.

5. Holt CA Course 1 10-1 Perimeter Find the perimeter of the figure. 2.8 + 3.6 + 3.5 + 3 + 4.3 Add all the side lengths. The perimeter is 17.2 in.

6. Holt CA Course 1 10-1 Perimeter Find the perimeter of the figure. 3.3 + 3.3 + 4.2 + 4.2 + 3 Add all the side lengths. 3.3 in. 4.2 in. 3 in. The perimeter is 18 in.

7. Holt CA Course 1 10-1 Perimeter

8. Holt CA Course 1 10-1 Perimeter Find the perimeter P of the parallelogram. P = 2l+ 2w Substitute 12 for l and 3 for w. P = (2 12) + (2 3) P = 24 + 6 P = 30 Multiply. Add. The perimeter is 30 cm. 12 cm 3 cm

9. Holt CA Course 1 10-1 Perimeter Check It Out! Example 2 Find the perimeter P of the parallelogram. P = 2l + 2w Substitute 15 for l and 2 for w. P = (2 15) + (2 2) P = 30 + 4 P = 34 Multiply. Add. The perimeter is 34 cm. 15 cm 2 cm

10. Holt CA Course 1 10-1 Perimeter A. What is the length of side a if the perimeter equals 1,471 mm? P = sum of side lengths Use the values you know. 1,471 = 416 + 272 + 201 + 289 + a 1,471 = 1,178 + a 1,471 – 1,178 = 1,178 + a – 1,178 Add the known lengths. Subtract 1,178 from both sides. 293 = a Side a is 293 mm long. Find each unknown measure.

11. Holt CA Course 1 10-1 Perimeter Find each unknown measure. B. What is the perimeter of the polygon? Step 1: Find b. Find the sum of the lengths opposite side b. b = 50 + 22 b = 72 P = 72 + 55 + 50 + 33 + 22 + 22 P = 254 Step 2: Find the perimeter. The perimeter of the polygon is 254 cm.

12. Holt CA Course 1 10-1 Perimeter Lesson Quiz: Part I Find each perimeter. 1. 2. 9 cm 4 ft 5 6 __

13. Holt CA Course 1 10-1 Perimeter Lesson Quiz: Part II 3. What is the perimeter of a rectangle with length 22 cm and width 8 cm? 4. The width of a rectangle is 12 in. What is the perimeter of the rectangle if the length is 7 in. longer than the width? 60 cm 62 in.