Unit D: Percent, Ratio and Rate

1. Unit D: Percent, Ratio and Rate Math 8

2. What you need to Know Definitions: Percent � the number of parts per 100; the numerator of a fraction with a denominator of 100 (ex. ) Ratio � a comparison of 2 or more quantities with the same unit (ex. Hours to hour) Rate � a comparison of 2 quantities measured in different unit (ex. 100 km/h)

3. Percent Increase � to calculate a percent increase, divide the increase by the original amount, then write the quotient as a % (ex. )

4. Percent Increase � to calculate a percent increase, divide the increase by the original amount, then write the quotient as a % (ex. ) Percent Decrease � to calculate a percent decrease, divide the decrease by the original amount, then write the quotient as a % (ex. )

5. Discount � the amount by which a price is reduced Two Term Ratio � a comparison of 2 quantities with the same unit Three Term Ratio � a comparison of 3 quantities with the same unit Part-to-Whole Ratio � a ratio that compares a part of the whole to the whole (ex. 13 spades to 52 cards)

6. Part-to-Part Ratio � a ratio that compares a part of the whole to another part of the whole

7. Part-to-Part Ratio � a ratio that compares a part of the whole to another part of the whole Equivalent Ratios � having the same value (ex. )

8. Part-to-Part Ratio � a ratio that compares a part of the whole to another part of the whole (ex boys to girls in class) Equivalent Ratios � having the same value (ex. ) Proportion � a statement that two ratios are equal (ex. )

9. Unit Rate � a quantity associated with a single unit of another quantity (ex. 6m in 1 sec is a unit rate and is written as 6m/s)

10. Rules: Dividing by numbers that are powers of 10 When you divide by a number that is a power of 10 (ex. 10, 100, 1000, 10000, etc) you move the decimal to the left The decimal moves the number of spaces that the divisor has zeros

11. Examples

12. Multiplying by numbers that are powers of 10 When you multiply by as number that is a power of 10 (ex. 10, 100, 1000, 10000, etc) you move the decimal to the right The decimal moves the number of spaces that the multiplier has zeros

13. Examples

14. Decimals Place Value hundreds� - 900.0 tens�������� - 90.0 ones������� �- 9.0 tenths����� � - 0.9 hundredths�� - 0.09 thousandths��������� -��0.009 Ten thousandths - 0.0009 Hundred thousandths - 0.00009 millionths������������� - 0.000009

15. 1. Relating Fractions, Decimals and Percents Look at the pie chart on p. 234 of you text book Which event was the favourite? How did you know? Log balance � because it represents the largest part of the graph. The largest sector also represents the greatest % of students (35%)

16. How can you write 35% as a fraction? Remember that a % means per 100.

17. How can you write 35% as a decimal?

18. How can you write 35% as a decimal? We know that Since the faction has a denominator of 100 we can write 35% as a decimal by dividing by 100

19. Which event was least favorite? Bannok Baking (7%) Write as a fraction and as decimal?

20. Which event was least favorite? Bannok Baking (7%) Write as a fraction and as decimal?