1. Ratio and Proportions

2. Definition RATIO RATIOis a comparison between two different thingsEXAMPLE: Suppose there are thirty-five people, fifteen of whom are men, what is the ratio of WOMEN TO MEN? 20 to 15 – the ratio of women to men: 20 to 15 IMPORTANT – NOT 15 to 20 – the order is IMPORTANT! 2/3/2016www.numberbender.com2

3. Examples There are 16 ducks and 9 geese in a certain park. Express the ratio of ducks to geese in all three formats. 2/3/2016www.numberbender.com3 There are 18 black marbles, 11 blue marbles, and 12 brown marbles. What is the ratio of black marbles to blue marbles 16 to 9 16 : 9 16 / 9 18 to 11 18: 11 18 / 11

4. Solving Proportions There are 2 cats and 3 dogs in the store. Suppose there are 12 cats in the store, how many dogs are there? X=18 2/3/2016www.numberbender.com4 2X = 36 22 2X=(3)(12) 2 = 12 3X Cat : 2 : 12 Dog3X There are 18 dogs in the store

5. Solving Proportions If Jill has $15, and Jack has $5, then Jill has 30 more than Jack. How much money does Jack have? X=10 2/3/2016www.numberbender.com5 15X = 150 15 15X=(30)(5) 15 = 30 5X Jill : 15 : 30 Jack5X Jack has $10 is his pocket.

6. More Practice 2/3/2016www.numberbender.com6 2 : P 820 4 : M 69 5 : Z 69 7 : B 518 P = 5 M = 6

7. Classwork 2/3/2016www.numberbender.com7 x = 6 x = 9 x = 16 x = 6 x = 14 x = 8 x = 6