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Warm-Up

Warm-Up. Write the following numbers in standard notation. a. 7.38 x 10 9 b. 5.7 x 10 -8. 7380000000 0.000000057 5/10 or 1/2 10/5 or 2/1

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Warm-Up

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  1. Warm-Up • Write the following numbers in standard notation. a. 7.38 x 109 b. 5.7 x 10-8 7380000000 0.000000057 5/10 or 1/2 10/5 or 2/1 38/56 56/3856/94 12 miles • Friday’s Lunch Detention: 5 girls, 10 boys • Write the ratio of girls to boys. • Write the ratio of boys to girls. • Thursdays assembly total. 38 girls & 56 boys • Write the ratio of girls to boys. • Write the ratio of boys to girls. • Write the ratio of boys to total people at the assembly. • Fabiana hikes at a rate of 3 miles per hour. How far can she hike in 4 hours?

  2. Review Homework

  3. Daily Quiz 5.1 1. Write a ratio comparing the number of vowels to the number of consonants in this word: • Mathematics 2. Yesterday the fax machine at Granddaddy’s BBQ handled 29 incoming faxes and 59 outgoing faxes. Estimate the ratio of incoming faxes to outgoing faxes. 4/7 30/60 or 3/6 or 1/2

  4. Learn to solve proportions.

  5. Vocabulary Equal Ratios: Ratios that name the same amount -To find equal ratios: Multiply or divide the numerator and denominator by the same nonzero number.

  6. Qiana paid $12 for 40 minutes of airtime on her monthly cellular phone bill. Complete the table to find rates equal to 12:40. 6 24 160 10

  7. Donald paid $10 for 30 minutes of airtime on his monthly cellular phone bill. Complete the table to find rates equal to 10:30. 5 20 150 3

  8. Proportion: an equation stating that two ratios are equal.

  9. 6 15 ? 4 10 = 6 15 4 10 Using Cross Products to Identify Proportions Tell whether the ratios are proportional. 60 Find cross products. 60 60 = 60 Since the cross products are equal, the ratios are proportional.

  10. 5 10 ? 2 4 = 5 10 2 4 Tell whether the ratios are proportional. 20 Find cross products. 20 20 = 20 Since the cross products are equal, the ratios are proportional.

  11. Do the ratios form a proportion?

  12. 4 parts gasoline 1 part oil ? 15 quarts gasoline 5 quarts oil = Using Cross Products to Identify Proportions A mixture of fuel for a certain small engine should be 4 parts gasoline to 1 part oil. If you combine 5 quarts of oil with 15 quarts of gasoline, will the mixture be correct? Set up equal ratios. Find the cross products. 4 • 5 = 20 1 • 15 = 15 20 ≠ 15 The cross products are not equal. The mixture will not be correct.

  13. 3 parts tea 1 part sugar ? 12 tablespoons tea 4 tablespoons sugar = A mixture for a certain brand of tea should be 3 parts tea to 1 part sugar. If you combine 4 tablespoons of sugar with 12 tablespoons of tea, will the mixture be correct? Set up equal ratios. Find the cross products. 3 • 4 = 12 1 • 12 = 12 12 = 12 The cross products are equal. The mixture will be correct.

  14. Summarize Lesson HW: Practice 5.2 Remember work on your Explain It!

  15. 48 42 16 14 40 15 3 4 ? ? = = 6 9 n 24 n 12 45 18 = = Lesson Quiz Tell whether the ratios are proportional. yes no 1. 2. Solve each proportion. 4. n = 30 3. n = 16 5. An elevator travels 342 feet as it goes from the lobby of a building to the top floor. It takes 7 seconds to travel the first 133 feet. If the elevator travels at the same rate, how much longer does it take reach the top floor? 11s

  16. Lesson Quiz for Student Response Systems 1. Identify the ratios that are proportional. A. B. C. D.

  17. Lesson Quiz for Student Response Systems 2. Solve the given proportion. A. p = 8 B. p = 9 C.p = 10 D. p = 11

  18. Lesson Quiz for Student Response Systems 3. A 225 kg weight is positioned 5 m from a fulcrum. If a 300 kg weight is placed at the opposite end of the balance, how far from the fulcrum should it be positioned? A. 5.75 m B. 4.5 m C.4.25 m D. 3.75 m

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