(7) Lesson 2.3
- 1. Course 2, Lesson 2-3 Estimate. 1. 48% of 30 2. 8.5% of 268 3. 112% of 49 4. 83% of 79 5. Twenty-two percent of the seventh-grade class at Santa Ana Middle School has blue eyes. If the seventh-grade class has 139 students, about how many have blue eyes? 6. Write an estimate of 128% of 179?
- 2. Course 2, Lesson 2-3 ANSWERS 1. 15 2. 28 3. 55 4. 64 5. 28 6. 225
- 3. HOW can percent help you understand situations involving money? Ratios and Proportional Relationships Course 2, Lesson 2-3
- 4. Ratios and Proportional Relationships Course 2, Lesson 2-3 Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. 7.RP.3 Use proportional relationships to solve multistep ratio and percent problems. Mathematical Practices 1 Make sense of problems and persevere in solving them. 3 Construct viable arguments and critique the reasoning of others. 4 Model with mathematics.
- 5. To use the percent proportion to find: • the Percent • the Part, or • the Whole Ratios and Proportional Relationships Course 2, Lesson 2-3
- 6. Percent Proportion Ratios and Proportional Relationships Course 2, Lesson 2-3
- 7. Ratios and Proportional Relationships Course 2, Lesson 2-3 Find the percent What percent of 5 is 4? Find the part What number is 80% of 5? Find the whole 4 is 80% of what number? 4 5 = 100 n 8 5 0p = 100 4 80 w = 100 Type Example Proportion
- 8. 1 Need Another Example? 2 3 4 5 6 Step-by-Step Example 1. What percent of $15 is $9? Words Variable Proportion What percent of $15 is $9? Let n represent the percent. part whole percent Write the proportion. 9 100 = 15 n Find the cross products. 900 = 15n Simplify. Divide each side by 15. 60 = n So, $9 is 60% of $15.7
- 9. Answer Need Another Example? What percent of 24 is 18? 75%
- 10. 1 Need Another Example? 2 3 4 5 6 Step-by-Step Example What number is 40% of 120?2. Words Variable Proportion What number is 40% of 120? Let p represent the part. part whole percent Write the proportion. Find the cross products. Simplify. p 100 = 120 40 100p = 4,800 Divide each side by 100. p = 48 So, 48 is 40% of 120.
- 11. Answer Need Another Example? What number is 30% of 150? 45
- 12. 1 Need Another Example? 2 3 4 5 6 Step-by-Step Example 3. 18 is 25% of what number? Words Variable Proportion 18 is 25% of what number? Let w represent the percent. part whole percent Write the proportion. Find the cross products. Simplify. 18 100 = w 40 1,800 = 25w Divide each side by 25. 72 = w So, 18 is 25% of 72.
- 13. Answer Need Another Example? 12 is 80% of what number? 15
- 14. 1 Need Another Example? 2 3 4 5 6 Step-by-Step Example 4. The average adult male Western Lowland gorilla eats about 33.5 pounds of fruit each day. How much food does the average adult male gorilla eat each day? You know that 33.5 pounds is the part. You need to find the whole. Write the proportion. Find the cross products. Simplify. Divide each side by 67. 33.5 100 = w 67 3,350 = 67w 50 = w The average adult male gorilla eats 50 pounds of food each day. 7
- 15. Answer Need Another Example? Sally read the nutrition facts on a box of her favorite cereal. Each cup of the cereal provides 7% of the recommended daily value of potassium. If a cup of the cereal contains 260 milligrams of potassium, what is the recommended daily value of potassium? Round your answer to the nearest whole number. about 3,714 mg.
- 16. How did what you learned today help you answer the HOW can percent help you understand situations involving money? Course 2, Lesson 2-3 Ratios and Proportional Relationships
- 17. How did what you learned today help you answer the HOW can percent help you understand situations involving money? Course 2, Lesson 2-3 Ratios and Proportional Relationships Sample answers: • You can use the percent proportion to solve situations involving money.
- 18. The next lesson will be about solving problems using the percent equation. Predict what the percent equation might look like since it is based on the percent proportion. Ratios and Proportional RelationshipsRatios and Proportional Relationships Course 2, Lesson 2-3