7 -1 Ratios and Rates A ratio is

7 -1 Ratios and Rates A ratio is a comparison of two quantities using division. Ratios can be written to compare a part to a part, a part to the whole, or the whole to a part.

7 -1 Ratios and Rates Example 1 Use the table to write the ratio. Animals at the Vet Cats 5 Dogs 7 Rabbits 2 cats to rabbits Part to part

7 -1 Ratios and Rates Example 2 Use the table to write the ratio. Animals at the Vet Cats 5 Dogs 7 Rabbits 2 dogs to total number of pets Part to whole

7 -1 Ratios and Rates Example 3 Use the table to write the ratio. Animals at the Vet Cats 5 Dogs 7 Rabbits 2 total number of pets to cats Whole to part

7 -1 Ratios and Rates Example 5 Use the table to write each ratio. Animals at the Vet Birds 6 Hamsters 9 Snakes 3 birds to total number of pets

7 -1 Ratios and Rates Example 6 Use the table to write the ratio or rates. Animals at the Vet Birds 6 Hamsters 9 Snakes 3 snakes to hamsters

7 -1 Ratios and Rates Equivalent ratios are ratios that name the same comparison. You can find an equivalent ratio by multiplying or dividing both terms of a ratio by the same number.

7 -1 Ratios and Rates Example 7 Write three equivalent ratios to compare the number of diamonds to the number of spades in the pattern. number of diamonds number of spades =

7 -1 Ratios and Rates Example 8 Write three equivalent ratios to compare the number of triangles to the number of hearts in the pattern.

7 -1 Ratios and Rates A rate compares two quantities that have different units of measure. Suppose a 2 -liter bottle of soda costs $1. 98. rate = price $1. 98 _______ = number of liters 2 liters $1. 98 for 2 liters When the comparison is to one unit, the rate is called a unit rate. Divide both terms by the second term to find the unit rate = $1. 98 $0. 99 for 1 liter _____ $1. 98 ÷ 2 _____ = = 2 2÷ 2 1 When the prices of two or more items are compared, the item with the lowest unit rate is the best deal.

7 -1 Ratios and Rates Example 8 A 3 -pack of paper towels costs $2. 79. A 6 -pack of the same paper towels costs $5. 46. Which is the better deal? $2. 79 _____ 3 rolls Write the rate. Divide both terms by 3. $5. 46 _____ 6 rolls Write the rate. Divide both terms by 6. The _________is the better deal.

7 -1 Ratios and Rates Example 9 A 3 -pack of juice boxes costs $2. 10. A 9 -pack costs $5. 58. Which is the better deal?

7 -1 Ratios and Rates Example 10 A 24 oz bottle of apple juice costs $5. 76. A 12 oz bottle of apple juice costs $3. 84. Which is the better deal?

7 -1 Ratios and Rates Lesson Quiz Use the table to write ratio. each 1. tulips to daffodils 9: 17 2. crocuses to total number of bulbs 20: 51 3. total bulbs to lilies 51: 5 4. A dozen eggs cost $1. 25 at one market. At a 1 __ competing market, 1 dozen eggs cost $2. 00. 2 Which is the better buy? eggs from the first market

7 -1 Ratios and Rates Lesson Quiz for Student Response Systems 1. Use the table to identify the ratio of lions to elephants. A. 8: 7 B. 8: 12 C. 7: 8 D. 7: 12 Animals in a Zoo Lions 8 Tigers 12 Elephants 7 Others 15

7 -1 Ratios and Rates Lesson Quiz for Student Response Systems 2. Use the table to identify the ratio of game CDs to total number of CDs. A. 25: 8 B. 17: 8 Gina’s CD Collection Music 5 C. 8: 17 Games 8 D. 8: 25 Cartoons 12

7 -1 Ratios and Rates Lesson Quiz for Student Response Systems 3. Use the table to identify the ratio of total number of grades to number of students with a C. A. 9: 30 Grades on Final Exam B. 9: 21 A 8 C. 21: 9 B 13 C 9 D. 30: 9

7 -1 Ratios and Rates Lesson Quiz for Student Response Systems 4. Jeff sells a pack of 36 pencils for $3. 25. Betsy sells a pack of 12 pencils for $1. 50. Which is the better buy? A. a pack of 12 pencils from Betsy B. a pack of 36 pencils from Jeff C. Both D. None