1. To Start: 20 Points!! -2(4x + 3y – 4z – 11) 12(11) + 12(14) + 12(24) – 12(9) Use front-end estimation: 6.3 + 8.55 Estimate the quotient: 29.5 ÷ 4.83 -8x – 6y + 8z +22 480 14.9 6

2. CHAPTER 3: DECIMALS AND EQUATIONS Section 3.4: Using Formulas

3. Vocabulary Formula is an equation that shows a relationship between quantities that are represented by variables. Example d=rt distance = rate x time The Perimeter of a figure is the distance around the figure. Example P=2w+2l

4. Using Formulas Suppose you travel 162 miles in 3 hours. Use the formula d=rt to find your average speed. Distance is 162 miles, so d=162. Time is 3 hours, so t=3 162 miles = r(3 hours), so now solve for r. Divide each side by 3. r = 162/3 = 54 mph!!

5. Using d = r(t) d = 273 mi t = 9.75 hours 273 = r(9.75) r = 28 mph d = 540.75 in r = 10.5 in/yr 540.75 = (10.5)t t = 51.5 yrs

6. Crickets!!! You can estimate the temperature outside using the chirps of a cricket. Use the formula F = n/4 + 37, where n is the number of chirps a cricket makes in one minute, and F is the temperature in degrees Fahrenheit. Estimate the temperature when a cricket chirps 100 times in a minute. The temperature is about 62 o

7. Crickets!!! Use the formula to estimate the temperature in degrees Fahrenheit for 96 chirps per minute. The temperature is about 61 o

8. Crickets – You Try!!! Use the formula to estimate the temperature in degrees Fahrenheit for 88 chirps per minute. The temperature is about 59 o

9. Crickets – You Try!!! Use the formula to estimate the temperature in degrees Fahrenheit for 66 chirps per minute. The temperature is about 53.5 o

10. Perimeter!!!! Find the perimeter of the room, Use the formula for the perimeter of a rectangle. 12.5 ft 18.5 ft

11. Perimeter – You Try!!!! Find the perimeter of the room, Use the formula for the perimeter of a rectangle. 16.8 cm 27.3 cm

12. Perimeter – You Try!!!! Find the perimeter of the room, Use the formula for the perimeter of a rectangle. 8.6 in 17.4 in

13. Homework!!! Page 139: 1-4, 10-17, 20