2. Warm Up What property is each showing? (a + b) + c = a + (b + c) a (b + c) = ab + ac a + b = b + a (a ∙ b) ∙ c = a ∙ (b ∙ c) ab = ba Distributive Commutative Prop. Of Addition Commutative Prop. Of Multiplication Associative Prop. Of Addition Associative Prop. Of Multiplication

3. What is a ratio? …a comparison of two quantities

4. Ratios can be written in three ways: Using the word “to8 to 12 With a colon8 : 12 As a fraction8 12

5. Write the ratio of the number of boys in our room to the number of girls. Using the word “to With a colon As a fraction Do you get the same ratio if you compare the number of girls to the number of boys?

6. A pet store has 4 puppies, 2 kittens, 5 birds, and 3 hamsters. Write the ratio of kittens to birds in 3 ways. Write the ratio of puppies to all animals in three ways.

7. Equal Ratios What do you think they are?? Two ratios are equivalent if they can be written as equivalent fractions.

8. Equal Ratios How can you tell if two ratios are equal? The answer : Cross Products!

9. 496 to 8, 15 to 20 510 3:4, 18:24 CHECKPOINT Tell whether the ratios are equivalent using cross products.

10. Equal Ratios Fire Hydrants to City Blocks 2 3

11. State an equal ratio to… all in different forms 5:93/8 60 to 100 1: 13

12. State an equal ratio to… all in different forms For every 12 pie slices sold at the Circus Café, 4 are cherry. Find one equal ratio using multiplication and one using division.

13. Homework TB p385 #9a,b.c TB p388 1-4, 9-17