1. Ratio and Proportions

2. A "ratio" is just a comparison between two different things. Suppose there are thirty-five people, fifteen of whom are men, what is the ratio of WOMEN TO MEN? Example: the ratio of women to men: " 20 to 15 " NOT " 15 to 20 " the order is IMPORTANT!

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

4. Solving proportion There are 2 cats and 3 dogs in the store. Suppose there are 12 cats in the store, how many dogs are there? Cat Dog 2 3 :: x 12 2 3 = x 2x (3)12 =2x 36 = 2 2 X = 18 There are 18 dogs in the store

5. If Jill has $ 15, and Jack has $ 5, then Jill has 30 more than Jack. How much money does Jack have? Solving proportion Jill Jack 15 5 :: x 30 15 5 = 30 x 15x (30)5 =15x 150 = 15 X = 10 Jack has $10 in his pocket.

6. MORE PRACTICE 2 8 : 20 x 7 5 : 18 x 5 6 : 9 x 4 6 : 9 m X=5X=6X=45/6X=126/5

7. CLASSWORK 2 3 : x 4 x 4 : 2 8 x 2 : 3 7 6 2 : 3 x X=6X=9X=14/3X=16 5 2 : x 15 x 3 : 6 12 x 2 : 3 7 2 : 4 x X=6X=14X=8X=6 SHOW YOUR WORK!