1. Holt CA Course 1 5-1 Ratios NS1.2 Interpret and use ratios in different contexts (e.g., batting averages, miles per hour) to show the relative sizes of two quantities, using appropriate notations (, a to b, a:b). California Standards a ba b

2. Holt CA Course 1 5-1 Ratios Vocabulary ratio

3. Holt CA Course 1 5-1 Ratios In basketball practice. Kathlene made 17 baskets in 25 attempts. She compared the number of baskets she made to the total number of attempts she made by using the ratio. A ratio is a comparison of two numbers or quantities. 17 25 Kathlene can write her ratio of baskets made to attempts in three different ways. 1725 17 to 25 17:25

4. Holt CA Course 1 5-1 Ratios Twenty students are asked to choose their favorite music category. Eight chose pop, seven chose hip hop, and five chose rock. Write each ratio in all three forms. Teacher Example 1A: Writing Ratios rock to hip hop 5757 The ratio of rock to hip hop can be written as, 5 to 7, 5:7. There are 5 who choose rock and 7 who choose hip hop. rock hip hop = 5757

5. Holt CA Course 1 5-1 Ratios Twenty students are asked to choose their favorite music category. Eight chose pop, seven chose hip hop, and five chose rock. Write each ratio in all three forms. Teacher Example 1B: Writing Ratios hip hop to pop hip hop pop 7878 The ratio of hip hop to pop can be written as, 7 to 8, 7:8. = 7878 There are 7 who choose hip hop and 8 who choose pop.

6. Holt CA Course 1 5-1 Ratios Twenty students are asked to choose their favorite music category. Eight chose pop, seven chose hip hop, and five chose rock. Write each ratio in all three forms. Teacher Example 1C: Writing Ratios rock to pop and hip hop rock t pop & hip hop = 5 15 There are 5 who choose rock, 8 who choose pop, and 7 who choose hip hop. The ratio of rock to pop and hip hop can be written as 5 15, 5 to 15, 5:15.

7. Holt CA Course 1 5-1 Ratios Student Practice 1A: snow boarding rock climbing 6969 The ratio of snow boarding to rock climbing can be written as, 6 to 9, 6:9. = 6969 There are 6 who choose snow boarding and 9 who choose rock climbing. Nineteen students are asked to choose their favorite sport. Nine chose rock climbing, four chose kite surfing, and six chose snow boarding. Write each ratio in all three forms. snow boarding to rock climbing

8. Holt CA Course 1 5-1 Ratios Student Practice 1B: kite surfing snow boarding 4646 The ratio of kite surfing to snow boarding can be written as, 4 to 6, 4:6. = 4646 There are 4 who choose kite surfing and 6 who choose snow boarding. Nineteen students are asked to choose their favorite sport. Nine chose rock climbing, four chose kite surfing, and six chose snow boarding. Write each ratio in all three forms. kite surfing to snow boarding

9. Holt CA Course 1 5-1 Ratios Student Practice 1C: rock climbing kite surfing and snow boarding = 9 10 There are 9 who choose rock climbing, 4 who choose kite surfing, and 6 who choose snow boarding. The ratio of rock climbing to kite surfing and snow boarding can be written as 9 10, 9 to 10, 9:10. rock climbing to kite surfing and snowboarding Nineteen students are asked to choose their favorite sport. Nine chose rock climbing, four chose kite surfing, and six chose snow boarding. Write each ratio in all three forms.

10. Holt CA Course 1 5-1 Ratios Sometimes a ratio can be simplified. To simplify a ratio, first write it in fraction form and then simplify the fraction.

11. Holt CA Course 1 5-1 Ratios A fraction is in simplest form when the GCD of the numerator and denominator is 1. Remember!

12. Holt CA Course 1 5-1 Ratios On average, most people can read about 600 words in 3 minutes. Write the ratio of words to minutes in all three forms. Write your answer in simplest form. Teacher Example 2: Writing Ratios in Simplest Form words minutes Write the ratio as a fraction. 600 ÷ 3 3 ÷ 3 = 600 3 Simplify. For every minute, there are 200 words read. words minutes = words minutes = 200 1 The ratio of words to minutes is 200 to 1.

13. Holt CA Course 1 5-1 Ratios At Casitas Middle School, there are 456 microscopes for 152 students. Write the ratio of microscopes to students in all three forms. Write your answer in simplest form. Student Practice 2: microscopes students Write the ratio as a fraction. 456 ÷ 152 152 ÷ 152 = 456 152 Simplify. For every microscope, there are 3 students. microscopes students = microscopes students = 3131 The ratio of microscopes to students is 3 to 1.

14. Holt CA Course 1 5-1 Ratios To compare ratios, write them as fractions with common denominators. Then compare the numerators.

15. Holt CA Course 1 5-1 Ratios Honey-lemon cough drops come in packages of 30 drops per 10-ounce bag. Cherry cough drops come in packages of 24 drops per 6-ounce bag. Tell which package has the greater ratio of drops to ounces. Teacher Example 3: Comparing Ratios Honey-lemonCherry Drops3024 Ounces106 Honey-lemon: drops ounces = 30 10 = 3131 Cherry: drops ounces = 24 6 = 4141 Because 4 > 3 and the denominators are the same, the drops to ounces is greater in the bag of cherry cough drops. Write the ratios as fractions with common denominators.

16. Holt CA Course 1 5-1 Ratios Mixed nuts come in small packages of 25 per 5 ounce package and large packages of 56 per 8 ounce package. Tell which bag has the greater ratio of mixed nuts per ounce. Student Practice 3: LargeSmall Mixed nuts5625 Ounces85 Large: mixed nuts ounces = 56 8 = 7171 Small: mixed nuts ounces = 25 5 = 5151 Because 7 > 5 and the denominators are the same, the large package has the greater ratio of mixed nuts to ounces. Write the ratios as fractions with common denominators.

17. Holt CA Course 1 5-1 Ratios Lesson Quiz: Part I A coin bank contains 16 quarters, 12 dimes, and 8 nickels. Write the given ratio in all three forms. 1. nickels to quarters 2. dimes to nickels 3. nickels and dimes to quarters 8 16, 8 to 16, 8:16 or 1212, 1 to 2, 1:2 20 16, 20 to 16, 20:16 or 5454, 5 to 4, 5:4 12 8, 12 to 8, 12:8 or, 3 to 2, 3:2 3232

18. Holt CA Course 1 5-1 Ratios Lesson Quiz: Part II 4. There are 220 calories in 5 crackers. Write the ratio of calories to crackers in simplest form. 5. On a school trip, Bus 1 has 3 teachers and 14 students. Bus 2 has 4 teachers and 28 students. Which bus has the greater ratio of teachers to students? Bus 1 44 calories 1 cracker, 44 to 1, 44:1