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10/22/2014 3-2 A Ratio Tables

Ratio table- a table filled with pairs of numbers that have the same ratio

Equivalent ratios- express the same relationship between 2 quantities- “scaling forward”- increase the numbers - “scaling back”- decrease the numbers

Example 1A recipe calls for 5 cups of water for each cup of black beans. How many cups of water should be used for 4 cups of black beans.

Use 20 cups of water for 4 cups of beans.

Example 2The state flower of Florida is the orange blossom. Find how many petals an orange blossom has.

One orange blossom has 5 petals.

5

Example 3Mrs. Lee used 12 yards of fabric to make 9 shirts. Find the number of shirts she could make with 20 yards of fabric.

There is no whole number by which you can multiply 12 to get 20. We need to use scaling!

Example 3

Mrs. Lee could make 15 blouses with 20 yards of fabric.

Several groups of friends are going to take a bus to the park. The table shows how much the different groups will pay in all. Predict how much a group of 15 friends will pay.

362412Bus Fare($)

18126Number in Group

12< 15 < 18; therefore, the group will pay between $24 and $36.

Example 4

A group of 15 friends will pay $30 in bus fare.

Your Turn

1.)

2.)

A recipe calls for 2 cups of water for each cup of rice. How many cups of water should be used for 3 cups of rice? Make a ratio table.

6 cups of water

In an orange peeling contest, Will peeled 18 oranges in 60 seconds. If he peeled the oranges at a constant rate, determine about how many oranges he peeled in 10 seconds.

3 oranges

Homework

• Pg. 166 #1 -20 Evens• Ch. 3 Quiz Tomorrow. • Ch. 2 Test Corrections due Friday.