Ratios

A ratio is… A comparison between two quantities. For every x units of one quantity, there are y units of another.

Ratios can be written in 3 ways: Using a colon 2:3 As a fraction 2 3 With the word, “to” 2 to 3

Ratios can show three scenarios: Part to part Part to whole Whole to part

Part to Part Blue to Yellow 5:4 5 4 5 to 4

Part to Whole Blue to Total 5:9 5 9 5 to 9

Whole to Part Total to Yellow 9:4 9 4 9 to 4

Example 1: A sixth grade basketball team has 3 centers, 5 forwards, and 6 guards. Write a ratio for each comparison using a colon: Forwards to guards (part to part) 5:6 Centers to total (part to whole) 3:14 Total to guards (whole to part) 14:6

Example 2: Martine’s quilt is made of 6 red squares and 18 blue squares. Write a ratio for each comparison using the fraction. Red to blue (part to part) 6 18 Red to total (part to whole) 6 24 Total to blue (whole to part) 24 18

Example 3: Gene has a movie collection. He has 9 Adventure movies, 8 Horror, 5 Sci-Fi, and 12 Comedy. Write a ratio for each comparison using the word, “to.” Horror to comedy (part to part) 8 to 12 Sci-Fi to total (part to whole) 5 to 34 Total to Adventure (whole to part) 34 to 9

Equivalent Ratios 2:3 is the same as 4:6 or 6:9 9 to 5 is the same as 18 to 10 or 81 to 45

Draw the following ratios, using squares and circles: 4:4 5 9 9 to 3

Write the following ratios in all three ways:

Write an equivalent ratio 70:35 8 6 14 to 15