Pre-Algebra Chapter 6 - Ramsey School District

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Fractions, Decimals, and Percents Vocabulary • percent • Express percents as fractions and vice versa. • Express percents as decimals and vice versa. are percents related to fractions and decimals? A portion of each figure is shaded. a. Write a ratio that compares the shaded region of each figure to its total region as a fraction in simplest form. b. Rewrite each fraction using a denominator of 100. c. Which figure has the greatest part of its area shaded? d. Was it easier to compare the fractions in part a or part b? Explain. Reading Math Percent Root Word: Cent There are 100 cents in one dollar. Percent means per hundred or hundredths. PERCENTS AND FRACTIONS A percent is a ratio that compares a number to 100. The meaning of 75% is shown at the right. In the figure, 75 out of 100 squares are shaded. To write a percent as a fraction, express the ratio as a fraction with a denominator of 100. Then simplify if possible. Notice that a percent can be greater than 100% or less than 1%. Example 1 Percents as Fractions Express each percent as a fraction in simplest form. a. 45% b. 120% 45 45% 120% 1 2 0 1 00 100 9 6 2 0 5 or 11 5 c. 0.5% d. 83 1 3 % 0.5 0.5% 83 1 1 00 3 % 0.5 1 0 83 1 1 00 10 3 100 Multiply by 1 0 to eliminate 10 5 1 or 10 00 2 00 5 the decimal in the numerator. 250 1 or 5 6 3 100 2 83 1 3 100 The fraction bar indicates division. Lesson 6-4 Fractions, Decimals, and Percents 281
To write a fraction as a percent, write an equivalent fraction with a denominator of 100. Example 2 Fractions as Percents Express each fraction as a percent. a. 4 5 b. 9 4 4 5 80 or 80% 9 100 4 2 25 or 225% 100 PERCENTS AND DECIMALS Remember that percent means per hundred. In the previous examples, you wrote percents as fractions with 100 in the denominator. Similarly, you can write percents as decimals by dividing by 100. Percents and Decimals • To write a percent as a decimal, divide by 100 and remove the percent symbol. • To write a decimal as a percent, multiply by 100 and add the percent symbol. Study Tip Mental Math To divide a number by 100, move the decimal point two places to the left. To multiply a number by 100, move the decimal point two places to the right. Example 3 Percents as Decimals Express each percent as a decimal. a. 28% b. 8% 28% 28% Divide by 100 and 8% 08% Divide by 100 and 0.28 remove the %. 0.08 remove the %. c. 375% d. 0.5% 375% 375% Divide by 100 and 0.5% 00.5% Divide by 100 and 3.75 remove the %. 0.005 remove the %. Example 4 Decimals as Percents Express each decimal as a percent. a. 0.35 b. 0.09 0.35 0.35 Multiply by 100 0.09 0.09 Multiply by 100 35% and add the %. 9% and add the %. c. 0.007 d. 1.49 0.007 0.007 Multiply by 100 1.49 1.49 Multiply by 100 0.7% and add the %. 149% and add the %. You have expressed fractions as decimals and decimals as percents. Fractions, decimals, and percents are all different names that represent the same number. Decimal 3 4 Fraction 0.75 75% Percent 282 <strong>Chapter</strong> 6 Ratio, Proportion, and Percent
Page 1 and 2: Ratio, Proportion, and Percent •
Page 3 and 4: Ratios and Rates Vocabulary • rat
Page 5 and 6: Study Tip Look Back To review dimen
Page 7 and 8: Standardized Test Practice Extendin
Page 9 and 10: Using Proportions Vocabulary • pr
Page 11 and 12: TEACHING TIP Solve juice in origina
Page 13 and 14: 41. SNACKS The Skyway Snack Company
Page 15 and 16: Scale Drawings and Models Vocabular
Page 17 and 18: Interior Designer Interior designer
Page 19: 21. CRITICAL THINKING What does it
Page 23 and 24: Practice and Apply Homework Help Fo
Page 25 and 26: A Preview of Lesson 6-5 Using a Per
Page 27 and 28: Using the Percent Proportion • Us
Page 29 and 30: Example 4 Find the Part What number
Page 31 and 32: 25. LIFE SCIENCE Carbon constitutes
Page 33 and 34: Find the percent of each number men
Page 35 and 36: Practice and Apply Homework Help Fo
Page 37 and 38: Using Percent Equations Vocabulary
Page 39 and 40: Simple interest is the amount of mo
Page 41 and 42: 42. CRITICAL THINKING Determine whe
Page 43 and 44: Percent of Change Vocabulary • pe
Page 45 and 46: PERCENT OF DECREASE When the amount
Page 47 and 48: Standardized Test Practice 26. RESE
Page 49 and 50: Probability and Predictions Vocabul
Page 51 and 52: USE A SAMPLE TO MAKE PREDICTIONS No
Page 53 and 54: Standardized Test Practice 37. FOOD
Page 55 and 56: Vocabulary and Concept Check base (
Page 57 and 58: Chapter 6 Study Guide and Review 6-
Page 59 and 60: • Extra Practice, see pages 736-7
Page 61 and 62: Part 1 Record your answers on the a

Pre-Algebra Chapter 6 - Ramsey School District

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