Bell Work Find the slope Slope = 0 Slope =

Ratios

There are 3 ways to express ratios : There are 3 ways to express ratios : As a fraction - ¾ Using a colon - 3:4 Using the word “to” - 3 to 4

What is the ratio of cats to mice? Number of Cats: 3 Number of Mice: 6 Express the ratio as a fraction: Express the ratio in words: Express the ratio with a colon: 3 to 6 3:6

TeamWinsLosses S.D. Padres1611 L.A. Dodgers1813 Chicago Cubs Spring Training List the wins to losses by the Cubs :17 to 14 Wins to games played: 17 to 31 List the losses to wins by the Padres:11/16 Losses to games played:11/27

TeamWinsLosses S.D. Padres1611 L.A. Dodgers1813 Chicago Cubs Spring Training List the Dodgers wins to total games: 18 : 31 List the Dodgers losses to wins: 13 : 18

Your face uses about 13 muscles to smile and about 43 muscles to frown. Write the ratio of muscles used for frowning to muscles used for smiling in three different ways. 43:13 43/13 43 to 13

Comparing Ratios Seth and Nathan compared their CD collections. To determine who has a greater ratio of rock CDs to pop CDs, write the ratios. RockPopHip-hop Seth92316 Nathan Seth: =.375 Nathan: = 0.6 Write ratios as fractions. Write fractions as decimals to compare. Nathan has a greater ratio of rock to pop CDs.

How do you change a fraction into a decimal? Divide the denominator into the numerator OR on your calculator hit 9 divided by 24 =.375

Ratio? Ratio is a way of comparing two or more quantities Examples: ◦Number of Red Smarties in a box compared to Blue ◦Number of girls in a class compared to boys

For example RED & BLUE Smarties 6 BLUE3 RED “The Ratio of BLUE to RED Smarties is 6 to 3 Blue : Red 6 : 3 2 : 1 “The Ratio of BLUE to RED Smarties is 6

…. Or… RED & BLUE Smarties 6 BLUE3 RED “The Ratio of RED to BLUE Smarties is 3 to 6” Red : Blue 3 : 6 1 : 2 “The Ratio of RED to BLUE Smarties is 1:2” “For every RED Smartie, there are 2 BLUES”

Simplifying Ratios In the Smarties example, we changed 6:3 to 2:1 This is called Simplifying a ratio We did it by dividing each number by 3 3 was the largest common factor

Try to simplify these 8:2 18:3 4:8 5:25 5:2 4:1 6:1 1:2 1:5 5:2 !!

Sharing an amount in a given ratio “Bart and Maggie share a bag of 16 life savers in the ratio 3:1” This means “for every 3 life savers Bart gets, Maggie gets 1” 412

What is a ratio? Example: There are 300 computers and 1200 students in our school. What is the ratio of computers to students? Express the ratio in words: Express the ratio as a fraction: A ratio is a comparison of two quantities. 300 to 1200 Express the ratio with a colon:300 : 1200 How many students are there for one computer?

Equivalent ratios make the same comparison. What is an Equivalent Ratio? 1.There are 300 computers for 1200 students Express the ratio as a fraction: 2.There is 1 computer for every 4 students OR Bring the fraction to lowest terms:

Practice With Equivalent Ratios Find an equivalent ratio by dividing:  Divide by 30 # 1 # 2  Divide by 3 # 3  Divide by 25

Practice With Equivalent Ratios Find an equivalent ratio by multiplying:  Multiply by 5 # 4 # 5 # 6  Multiply by 12  Multiply by 6

Practice: Ratios worksheet