2. 1.5 “Using Formulas”  A formula is an algebraic equation that relates two or more variables.

3. 1.5 “Using Formulas” ä Goal 1 -You should review or learn how to find area and perimeter. ä Goal 1 - You should review or learn how to find area and perimeter.  Important examples of formulas are those used to fined perimeter and area of triangles, rectangles and squares.

4. Triangle P = a + b + c A = ½ bh Perimeter - Area - a c h b

5. Rectangle P = 2 l + 2 w A = lw Perimeter - Area - l w w l

6. Square P = 4 s A = s 2 Perimeter - Area - s s s s

7. Example 1 – Finding Perimeter and Area Find the perimeter and area of the figure give that a = 10 ft, b = 6 ft, c = 8 ft, and d = 12 ft. b a c d Solution Find the perimeter by adding the side lengths. P = a + b + c + d

8. Example 1 – Finding Perimeter and Area Find the perimeter and area of the figure give that a = 10 ft, b = 6 ft, c = 8 ft, and d = 12 ft. b a c d Solution P = a + b + c + d P = 10 + 6 + 8 + 12 P = 36 The perimeter of the figure is 36 feet.

9. Example 1 – Finding Perimeter and Area Find the perimeter and area of the figure give that a = 10 ft, b = 6 ft, c = 8 ft, and d = 12 ft. 6 ft 10 ft 8 ft 6 ft 6 ft Solution Find the area by dividing the figure into a triangle and a rectangle as shown. 8 ft

10. Example 1 – Finding Perimeter and Area Find the perimeter and area of the figure give that a = 10 ft, b = 6 ft, c = 8 ft, and d = 12 ft. 6 ft 10 ft 8 ft 6 ft 6 ft Solution A= ½ bh + lw A= ½ (6)(8) + (6)(8) A= ½ (48) + 48 A= 24 + 48 8 ft

11. Example 1 – Finding Perimeter and Area Find the perimeter and area of the figure give that a = 10 ft, b = 6 ft, c = 8 ft, and d = 12 ft. 6 ft 10 ft 8 ft 6 ft 6 ft Solution A = 24 + 48 A = 24 + 48 A = 72 A = 72 The area of the figure is 72 ft 2. 8 ft

12. 1.5 “Using Formulas” ä Are there any questions about Using Formulas to Find Perimeter and Area?

13. 1.5 “Using Formulas” ä Goal 2 -You should review or learn how to use formulas to find distances. ä Goal 2 - You should review or learn how to use formulas to find distances. ä Algebraic expressions and equations are often used to model life-like and real quantities.

14. 1.5 “Using Formulas”  You can translate a verbal model into an algebraic model by using labels.  These algebraic models are sometimes called formulas.

15. Verbal Algebraic Verbal Algebraic Model  Label  Model Model  Label  Model Thedistancetraveled is the product of the rate and the time. d = distance r = rate (speed) (speed) t = time d = rt

16. Example 2 Finding a Distance ä A rover driving on the moon’s surface travels at a speed of 30 ft/min.  How far will it travel in 80 min?  Solution ä Verbal Model Distance = Rate x Time  Labels = d  Labels Distance = d (feet) = r  Rate = r (feet per minute) = t  Time = t (minutes)

17. ä Solution ä Verbal Model Distance = Rate x Time  Labels = d  Labels Distance = d (feet) = r  Rate = r (feet per minute) = t  Time = t (minutes)  Algebraic Model d = rt Write algebraic model.  = (30)(80) Substitute 60 for r and 90 for t.  = 2400 Multiply to Simplify. ä In 80 minutes the rover will travel 2400 ft.

18. 1.5 “Using Formulas” ä Are there any questions about Finding Distances?

19. Classwork: ä 930 Danny Dana ä 10/4 ä Math 7 - Dequer 1. 5 Pg.24-26: 1-4 and 24-26 1. Work Quietly and On-Your- Own ! We’ll go over, the Guided Practice, in a few minutes !

20. 1.2 “Guided Practice” Pg. 9: 1-22 P = 40 ft  1. P = 40 ft A = 88 ft 2  A = 88 ft 2 P = 44 in.  2. P = 44 in.  A = 104 in. 2 2400 ft  3. 2400 ft 67.5 m  4. 67.5 m C  24. C G  25. G D  26. D

21. Class/Homework Monday (10/4) u 1. u 1. Pgs. 24-26: 6, 8, 10, 12, 16 u 2. u 2. Work on 1 st 1 st Quarter Project or Assigned Replacement