1. April 23, 2009 “Energy and persistence conquer all things.” ~Benjamin Franklin

2. April 23, 2009 Section 5.4 (finish) Exploration 5.18 Section 6.1 – Ratio and Proportion

3. 5.4 (cont’d) Warm-up: Use an area model to compute the product: 3.2 × 2.6

4. 5.4 (cont’d) Ex: Express the decimal in expanded form: 3.279

5. 5.4 (cont’d) Rounding vs. estimating Ex: Round 2.047 to the nearest tenth Ex: Estimate 4.1 × 2.6

6. Exploration 5.18 Patterns in repeating decimals Part 1: 1.a. 1/11 = 0.090909… What do you think 2/11 will look like in decimal form? (check it) b. Predict 3/11, 4/11 and 5/11. c.Describe the pattern you see in words d.Predict 17/11

7. Exploration 5.18 Do with your group: #3, 5 and 6.

8. Section 6.1 – Ratio and Proportion Proportions: A comparison of equal fractions A comparison of equal rates A comparison of equal ratios

9. 6.1 (cont’d) Ratios and Rates If a : b = c : d, then a/b = c/d. If a/b = c/d, then a : b = c : d. Example: 35 boys : 50 girls = 7 boys : 10 girls 5 miles per gallon = 15 miles using 3 gallons

10. 6.1 (cont’d) Proportional word problems: Start easy: I can buy 3 candy bars for $2.00. So, at this rate, 6 candy bars should cost… 9 candy bars should cost… 30 candy bars should cost… 1 candy bar should cost… this is called a unit rate.

11. 6.1 (cont’d) Proportional word problems: Here’s another. 7 small drinks cost as much as 5 large drinks. At this rate… How much should 14 small drinks cost? How much should 21 small drinks cost? How much should 15 large drinks cost?

12. 6.1 (cont’d) Ratios are not the same as fractions The ratio of males to females is 3 : 2. That means 3/5 of the people are male, and 2/5 of the people are female. The ‘whole’ is the group of 5 people.

13. 6.1 (cont’d) Ratios are not the same as fractions The mixture is 3 parts water and 1 part green dye. That means that 3/4 of the mixture is water and 1/4 of the mixture is green dye. The ‘whole’ is the mixture, which consists of 4 total parts.

14. 6.1 (cont’d) Ratios are not the same as fractions A school’s enrollment increases by 25 students per year. This one can be expressed as a fraction – sort of: 25 students/1 year. There is no ‘whole’, though, since the two quantities being compared have different units!

15. Homework Link to online homework list: http://math.arizona.edu/~varecka/302AhomeworkS09. htm *Note: approximate grades are posted on D2L.