1. Fractions, Decimals and Percents
Lesson 12
Proportionality
Fractions, Decimals and Percents

2. Warm-Up Write a ratio in simplest form.
Six red balloons and 6 yellow balloons were used for a party.
Write the ratio of red balloons to yellow balloons used for the party.
Write the ratio of red balloons to all balloons used for the party.
Write the ratio of yellow balloons to all balloons used for the party.
Two similar figures have perimeters of 27 inches and 45 inches. What is the ratio of their areas?
Solve the proportion:

3. Fractions, Decimals and Percents
Target:
Convert between fractions, decimals and percents.

4. Vocabulary
Percent: A ratio that compares a number to 100.

5. Write Percents as Fractions and Decimals
To write a percent as a fraction, write the value of the percent in the numerator of the fraction and 100 in the denominator. Write the fraction in simplest form.
To write a percent as a decimal, write it as a fraction and then convert the fraction to a decimal.

6. Example 1 Write each percent as a fraction and a decimal. a. 25%
Convert to a fraction and simplify.
Convert to a decimal ÷ 4 = 0.25
25% = = 0.25
b. 88%
Convert to a decimal ÷ 25 = 0.88
88% = = 0.88

7. Example 2ab Write each decimal as a percent. a. 0.65
Method 1: Rewrite as a fraction
Method 2: Multiply by ·100 = 65%
b. 0.5
Method 1: Rewrite as a fraction
Method 2: Multiply by ·100 = 50%

8. Example 2c Write each decimal as a percent. c. 1.44
Method 1: Rewrite as a fraction
Method 2: Multiply by ·100 = 144%

9. Example 3a Write the fraction as a percent.
Method 1: Rewrite as fraction
Write the percent %
Method 2: Multiply decimal by 100.
Convert to a decimal.
Multiply by ·100 = 70
Write with % symbol %

10. Example 3b Write the fraction as a percent.
Method 1: Rewrite as fraction
Write the percent %
Method 2: Multiply decimal by 100.
Convert to a decimal.
Multiply by ·100 = 40
Write with % symbol %

11. Example 3c Write the fraction as a percent.
Method 1: Rewrite as fraction
3 does not divide evenly into use Method 2
Method 2: Multiply decimal by 100.
Convert to a decimal.
Multiply by 100.
Write with % symbol.

12. Exit Problems Write 15% as a fraction and a decimal.
Write 0.81 as a percent.
Write as a percent.

13. Communication Prompt Which do you prefer when writing a fraction as a
percent:
-rewriting the fraction with 100 in the denominator? OR
-writing the fraction as a decimal and multiplying the
decimal by 100? Why?