1. Lesson 3-7 Pages 131-136 Using Formulas

2. What you will learn! 1. How to solve problems by using formulas. 2. How to solve problems involving the perimeters and areas of rectangles.

3. FormulaPerimeter Area

4. What you really need to know! Formulas are sets of instructions that need to be followed. Write the formula. Replace the variables. Solve.

6. Example 1: If you travel 135 miles in 3 hours, what is your average speed in miles per hour? d = rt 135 = r(3) 45 = r 45 mph

7. Example 2: Find the perimeter of the rectangle. 70 cm 15 cm 20 cm p = 2 l + 2w p = 220 + 215

8. Example 3: The perimeter of a rectangle is 60 feet. Its width is 9 feet. Find its length. p = 2 l + 2w 60 = 2 l + 29 60 = 2 l + 18

9. Example 3: The perimeter of a rectangle is 60 feet. Its width is 9 feet. Find its length. 42 = 2 l 21 = l 21 feet 60 = 2 l + 18

10. a = l w a = 146 a = 84 ft 2 Example 4: Find the area of a rectangle with length 14 feet and width 6 feet. 84 ft 2 6 ft 14 ft Area Demo

11. Example 5: The area of a rectangle is 40 square meters. Its length is 8 meters. Find its width. a = l w 40 = 8w 5 = w 5 m

12. Page 133 Guided Practice #’s 4-9

14. Pages 131-133 with someone at home and study examples! Read:

15. Homework: Pages 134-136 #’s 10-32 even, 33-34, 38, 40 #’s 44-53 Lesson Check CH-3

21. Page 730 Lesson 3-7

22. Lesson Check CH-3

23. Study Guide and Review Pages 138-140 #’s 1-38 (Odd answers in back of book)

29. Prepare for Test! Page 141 #’s 1-25

33. Prepare for Test! Pages 142-143 #’s 1-19