Ratios. How are the numbers in each ad compared? Which ads are most effective?

Transcription

1 5 and part to part, part to whole versions of ratios There are different ways to compare numbers. these advertisments. How are the numbers in each ad compared? Which ads are most effective? 1

2 5 and part to part, part to whole versions of ratios A ratio says how much of one thing there is compared to another thing. What is the ratio of Dark hair to light hair in this room? 2

3 5 and part to part, part to whole versions of ratios 3

4 5 Collection of sports balls: two term ratio: compares ONE part to the collection and part to part, part to whole versions of ratios There are Ratio is: 7 to 20, or 7:20. compared to balls. You pronounce " : " as ratio. As a fraction, it is As a percent: _7_ = = % (Multiply N/D by 5) So, % of the balls are basketballs. 4

5 5 Collection of sports balls: part to part ratio: compares ONE part of the collection to another part of the collection and part to part, part to whole versions of ratios There are compared to. Ratio is: to, or : As a fraction or percent, it can't be done! Because?? 5

6 5 Two term ratio: any ratio that has two terms! Three term ratio: any ratio that has three terms! and part to part, part to whole versions of ratios REMEMBER THAT RATIOS SHOULD ALWAYS BE IN LOWEST TERMS!!! 4:2 = 2:1 8:12 = 2:3 These are equivalent ratios. 6

7 5 and part to part, part to whole versions of ratios Collection of sports balls: three term ratio: compares three parts of the collection There are compared to compared to. Ratio is: to to, or : : 7

8 5 and part to part, part to whole versions of ratios Part to Part Ratio a ratio that compares part of the whole to another part of the whole. Part to Whole a ratio that compares part of the whole to the whole. 8

9 5 Write Equivalent ratios The ratio of triangles to squares is 4:3. That means, for every 4 triangles, there are 3 squares. equivalent ratios. The ratio of triangles to squares is 8:6. There are still 3 squares for every 4 triangles. The ratios 8:6 and 4:3 are equivalent ratios. Equivalent ratios are equal. 8:6 = 4:3 An equivalent ratio can be formed by multiplying or dividing the terms of a ratio by the same number

10 5 Write Equivalent ratios equivalent ratios. 10

11 5 Write Equivalent ratios equivalent ratios. Write 3 ratios equivalent to: 2:5 36:6 11

12 5 Write Equivalent ratios equivalent ratios. Construction kits come in different sizes. The regular kit contains 120 long rods, 80 short rods and 40 connectors. List 3 other kits that could be created with the same ratio of rods and connectors. 12

13 5 Use Comparing different strategies to compare ratios. Option 1: Use equivalent ratios Who makes their coffee stronger? 13

14 5 Use Comparing different strategies to compare ratios. Option 2: Use equivalent rations with a 1 as the second term The recommended seeding on a package of grass seed is 200g per 9m 2. Carey spread 150g over 6.5m 2. Is this more than, equal to, or less than the recommended seeding? How do you know? 14

15 5 Use Comparing different strategies to compare ratios. a) Write each part to part ratio as a part to whole ratio. b) Write each part to whole ratio in fraction form. c) Write each part to whole ration as a percent. 2:3 4:3 15

16 5 Use Comparing different strategies to compare ratios. A contractor bought 2 shades of yellow paint for his clients. Shade 1 is made by mixing 5 cans of yellow paint with 3 cans of white paint. Shade 2 is made by mixing 7 cans of yellow paint with 4 cans of white paint. The clients should choose a lighter shade. Which shade should they choose? Step 1: Write the ratio of yellow paint to cans of white paint for each shade. Step 2: Write part to whole ratios for the number of cans of yellow paint to the total number of cans. Step 3: Write each part to whole ratio as a fraction. Step 4: Write each fraction as a percent. Step 5: Answer the question in a sentence. 16

17 5 Solving Ratio Problems Find the value of each variable. a) 5:x = 40:56 b) 49:35 = 14:n 17

18 18

19 5 Solving Ratio Problems In a recycle drive last week at Emerald Ridge, the grade 8's collected bottles and recycled some of them. The ratio of bottles recycled to bottles collected was 3:4. This week, the grade 8's collected 24 bottles. Miss Selinger told the students that the ratio of bottles recycled to bottles collected is the same as the ratio the preceding week. How can the students find how many bottles are recycled this week? 19

20 5 Solving Ratio Problems There is a photo of a father and his daughter standing beside each other. In the photo, the father's height is 8 cm and the daughter's height is 6 cm. The fathers actual height is 1.8 m. What is the actual height of his daughter? 20

21 5 Solving Ratio Problems A bike is in fourth gear. Then the pedal turns 3 times, the rear wheel turns 7 times. When the pedals turn twice, how many times does the rear wheel turn? 21

22 22