2. Objective 12/09/09 The students will be able to solve for the missing value in a proportion and solve word problems by using cross-products.

3. A PowerPoint Presentation by Mrs. Mary Angel Alim- Flores

4. Making Iced Tea Cups of water 123410 Iced Tea (tsp)

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8. Making Iced Tea Cups of water 123410 Iced Tea (tsp)481216

9. Making Iced Tea Cups of water 123410 Iced Tea (tsp)48121640

10. Two equal ratios form a PROPORTION. Ex. 5 : 10 = 20 : 40 56 = 7 56 = 7 64 8 64 8

11. 2 Ways of Writing a Proportion 2 Ways of Writing a Proportion 1. Colon Form 1. Colon Form 3:4 = 12: 16 3:4 = 12: 16 2. Fraction Form 2. Fraction Form 3 = 12 3 = 12 4 16 4 16

12. Extremes 16: 8 = 20:40 Means

13. To check if two ratios are equal or not: Fraction form  Use cross-products Ex. 3 = 15 Ex. 3 = 15 4 20 4 20 (3x20=60) (4x15=60) (3x20=60) (4x15=60) Therefore, the two ratios form a proportion.

14. 2. Colon form Check if the product of the means and product of the extremes are equal. Check if the product of the means and product of the extremes are equal. Ex. 4: 6 _____ 12: 18 (6x12= 72) (18x4= 72) (6x12= 72) (18x4= 72) Therefore, the two ratios are equal. Therefore, the two ratios are equal.

15. To solve for the missing value. UUUUse cross products 5 5 5 5 = 60 10 x

16. 5 5 = 60 10 x 1st Step: 5(x)= 5x 2nd Step: 10 (60)= 600 3rd Step: 5x = 600 5 5 Answer: x= 120

17. 12:36 = 3: m 1 st Step: 12 (m)= 12m 2 nd Step: 36 (3)= 108 3 rd Step: 12m = 108 12 12 12 12 Answer: m= 9

18. Solving Word Problems Grace and James are on a swimming team. Their swim training is 200 meters and usually takes them 3 minutes. How long, at this rate, would it take them to complete an 800- meter swim? Grace and James are on a swimming team. Their swim training is 200 meters and usually takes them 3 minutes. How long, at this rate, would it take them to complete an 800- meter swim?

19.  1. Set up the proportion: meters 200 = 800 meters 200 = 800 minutes 3 n minutes 3 n 2. Use cross-products 2. Use cross-products 200(n)= 200 n then 3(800)= 2400. 200(n)= 200 n then 3(800)= 2400. 3. Divide both sides by 200 3. Divide both sides by 200 n=12 n=12 Answer: 800-meter swim will take them 12 minutes. Answer: 800-meter swim will take them 12 minutes.

20. A car travels 125 miles in 3 hours. How far would it travel in 5 hours?

21. Step 1 Set up the proportion. Step 1 Set up the proportion. miles 125 = h miles 125 = h hours 3 5 hours 3 5 Step 2 Solve for the missing value (h). 125(5) = 625 then, 3(h)=3h 125(5) = 625 then, 3(h)=3h Step 3 Divide both 625 and 3h by 3 Answer: 208.33 or 208 1/3 miles Answer: 208.33 or 208 1/3 miles

22. RECAP Today I learned… The steps in solving proportions are…

23. Trip Around the World  1. U.S.A  2. Philippines  3. Australia  4. Canada  5. Japan

24. EXIT TICKET A 380- cubic cm sample of titanium has a mass of 1710 g. Find the weight of a titanium sample that has a volume of 532 cubic cm. Explain how you got your answer. A 380- cubic cm sample of titanium has a mass of 1710 g. Find the weight of a titanium sample that has a volume of 532 cubic cm. Explain how you got your answer.