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5-2 Solving Percent Problems Using Proportions

Video Tutor Help Finding a percent using proportionsFinding a percent using proportions (5-2) Finding part of a whole using proportionsFinding part of a whole using proportions (5-2) Find the whole amount using proportionsFind the whole amount using proportions (5-2) 5-2 Solving Percent Problems Using Proportions Khan Academy

Video Tutor Help Writing percents as fractions Writing percents as decimals Writing decimals as percents Ordering rational numbers with percents Writing fractions as percents Finding a percent using proportions Finding part of a whole using proportions Find the whole amount using proportions Using percent equations to find part of a whole Using percent equations to find a whole amount Finding sales tax Estimating using percents such as tips Finding simple interest Finding percent of increase Finding percent of markup Finding percent of discount

Worksheets Daily Notetaking Guide Worksheets Version A Practice, Guided Problem Solving Lesson 5-2 Practice 5-2 Guided Problem Solving 5-2

Vocabulary Practice Vocabulary (Electronic) Flash Cards Ratios, Rates, and Proportions Vocabulary 5A: Graphic Organizer Vocabulary 5B: Reading Comprehension Vocabulary 5C: Reading/Writing Math Symbols Vocabulary 5D: Visual Vocabulary Practice Vocabulary 5E: Vocabulary C Vocabulary 5F: Vocabulary Review Puzzle

Additional Lesson Examples Step-by-Step Examples Lesson 5-2

Lesson Readiness Lesson Quiz Problem of the Day Lesson 5-2

Percent Proportion In a percent proportion, one of the numbers, called the part, is being compared to the whole quantity, called the base. The other ratio is the percent, written as a fraction, whole base is = part base

Percent Proportion part base = percent 100 a b = p : where a is the part, b is the base, and p is the percent.

Percent Proportion part base = percent 100 a b = p : where a is the part, b is the base, and p is the percent. In percent problems, the base usually follows the word of.

Percent Problems Find the percent 7 is what percent of 10? Find the part What number is 70% of 10? Find the base 7 is 70% of what number? 7 10 = p 100 a 10 = b = percent part base

Example 5-1a Twenty is what percent of 25 ? Twenty is being compared to 25. So, 20 is the part and 25 is the base. Let p represent the percent. Replace a with 20 and b with 25. Find the cross products. Simplify. Find the Percent

Example 5-1b Divide each side by 25. Simplify. Answer: 20 is 80% of 25.

What percent of 150 is 45? LESSON 5-2 You can write a proportion to find the percent. Write the cross products. 150n = 45(100) 45 is 30% of 150. = n 100 Write a proportion. n = 30 Simplify. 150n 150 Divide each side by (100) 150 = Solving Percent Problems Using Proportions Additional Examples

Example 3-2a What number is 70% of 600? Answer: 420 is 70% of 600. The percent is 70, and the base is 600. You need to find the part. Replace b with 600 and p with 70. Find the cross products. Multiply. Divide each side by 100. Simplify. Find the Part

LESSON 5-2 Solving Percent Problems Using Proportions 35% of 90 is what number? Write the cross products. 100n = 90(35) 35% of 90 is = n Write a proportion. n = 31.5 Simplify. 100n 100 Divide each side by (35) 100 = Additional Examples

117 is 45% of what number? LESSON is 45% of 260. = 117 n Write the proportion. Write the cross products. 45n = 117(100) n = 260 Simplify. The model shows the relationship. Divide each side by n (100) 45 = Solving Percent Problems Using Proportions Additional Examples

Example 5-2a What percent of 8 is 12 ? Twelve is being compared to 8. So, 12 is the part and 8 is the base. Let p represent the percent. Replace a with 12 and b with 8. Simplify. Find the cross products. Find the Percent

Example 5-2b Answer: 150% of 8 is 12. Divide each side by 8. Simplify.

Example 5-4a What number is 8.8% of 20 ? The percent is 8.8, and the base is 20. Let a represent the part. Answer: 8.8% of 20 is Replace b with 20 and p with 8.8. Find the cross products. Simplify. Mentally divide each side by 100. Find the Part

Example 5-6a Seventy is 28% of what number? The percent is 28% and the part is 70. Let b represent the base. Replace a with 70 and p with 28. Find the cross products. Simplify. Find the Base

Example 5-6b Divide each side by 28. Simplify. Answer: 70 is 28% of 250.

Example 5-5a Recycling At Kington Middle School, 600 students were asked if their families recycle cans and/or newspapers. 32% said they recycle both; 25% said they recycle cans; 19% said they recycle newspapers; 24% said they do not recycle. How many families recycle both cans and newspapers? The total number of families is 600. So, 600 is the base. The percent is 32%. To find 32% of 600, let b represent the base, 600, and let p represent the percent, 32%, in the percent proportion. Let a represent the part. Apply the Percent Proportion

Example 5-5b Replace b with 600 and p with 32. Find the cross products. Simplify. Mentally divide each side by 100. Answer:192 families recycle both cans and newspapers.