Lesson 1: Ratios & Equivalent Ratios

Lesson 1:Ratios &

Equivalent Ratios

Part One - RATIOS

What do you know about ratios?

When have you seen or used ratios?

With your elbow partner:

What is a ratio?How many different ways can you write a ratio?

With your elbow partner:

A ratio COMPARES two quantities (numbers).

A ratio shows how much of one thing you have compared to something else.

Definition:

a to b

a:b

ab

All three are read as “the ratio of a to be”

Ratios can be written 3 different ways:

Click for Interactive Video

For each of the statements your

teacher reads out loud, write two ratios on your whiteboard.

For each of the ratios your

teacher reads out loud, create an

example on your whiteboard.

Complete Exploratory Challenge. (Save in math folder.)

Discuss answers with your team.

Part Two – EQUIVALENT RATIOS

What is an equivalent ratio? Create an example.

With your elbow partner:

How many different ways can you find equivalent ratios for:

2 boys to 3 girls

With your elbow partner:

How many different strategies can we share?

Class Discussion:

equivalent fractions multiplication tables tape diagram

Finding Equivalent Ratios:

The ratio of the length of Shanni’s ribbon to the length of Mel’s ribbon is 5 : 3 .

How much ribbon does Mel use if Shanni uses 45m?

Example #1 - Using Fractions

The ratio of the number of laps Mason ran to the number of laps Laney ran was 2 to 3.

If Mason ran 8 laps, how many did Laney run?

Example #2 - Using Multiplication

The ratio of the number of laps Mason ran to the number of laps Laney ran was 2 to 3.

Use a table to list 4 more equivalent ratios.

Example #3 - Using Tables

The ratio of the number of laps Mason ran to the number of laps Laney ran was 2 to 3.

Use a tape diagram to find how far Mason ran if Laney ran 930m.

Example #4 - Tape Diagram

In a bag of mixed nuts, the ratio of walnuts to cashews is 5 : 6.

Use a tape diagram to determine how many walnuts are in the bag if there are 54 cashews.

Example #5 - Tape Diagram

On a test, the ratio of the number of problems Josie got incorrect to the number of problems she got correct is 2:9.If Josie missed 8 problems, how many did she get right?

Example #6 - All strategies