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Unit 3B REVIEW

Unit 3B REVIEW. What is a ratio?. A group of students had a choice of either hamburgers or pizza for lunch. There were 12 students. 5 chose pizza and 7 chose hamburgers for lunch. What is a ratio (cont.). Ratios can be written to show: *part to whole *part to part

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Unit 3B REVIEW

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  1. Unit 3B REVIEW

  2. What is a ratio? A group of students had a choice of either hamburgers or pizza for lunch. There were 12 students. 5 chose pizza and 7 chose hamburgers for lunch.

  3. What is a ratio (cont.) • Ratios can be written to show: *part to whole *part to part *whole to part • Ratios can be written in 3 ways: *with a colon ( : ) *with the word “to” *as a fractions

  4. Write the Ratio in 3 Ways • triangles to stars • stars to circles • stars to shapes • circles to triangles

  5. Ratio - Application • 12 students tried out for the debate team. 7 students were selected. Write the ratio of students selected to those who tried out. 7:12

  6. Unit Rate • The value of 1 unit • Divide the total by the part EX: 450 miles on 15 gallons of gas

  7. Find the Unit Rate A group paid $600 for 12 concert tickets. How much did each ticket cost? $50 per ticket

  8. Find the Unit Rate 400 ounces of ice cream was purchased for 80 students. How many cups of ice cream does each student get? 5 ounces

  9. Equivalent Ratios

  10. Using the ratio on the previous slide, how much paint would you need to paint two sheds? • Amount needed to paint 2 sides of a shed. • 16 red cans; 4 white cans 16: 4

  11. Are the two ratios equivalent? • 4:2 = 12:6 • 5:10 = 1:2 • 1:4 = 4:1 • 1:2 = 2:3 • 3:1 = 9:3 • 1:6 = 2:12 Yes Yes No No Yes Yes

  12. Proportion *Two ratios that are equal to each other. *Can be used to find an unknown value

  13. Solve the Proportion r = 7 r = 28 7w = 42 6 7w = 252 7 7 w = 36 5a = 4 14 5a = 56 5 5 a = 11.2

  14. Solve the Proportion

  15. Solve the Proportion

  16. Set up a proportion to solve the problem Ms. Smith’s homeroom has 12 car riders. The ratio of car riders to walkers is 6:3. How many students in Ms. Smith’s homeroom walk to school? 6 walkers

  17. Set up a proportion to solve the problem A recipe calls for 2 eggs to make 10 pancakes. How many eggs will you need to make 35 pancakes? 7 eggs

  18. Set up a proportion to solve the problem Brooke drove 50 miles in 2 hours at a constant speed. Use a proportion to figure out how long it took her to drive 150 miles at the same speed. 6 hours

  19. Change a fraction to a decimal • Divide the numerator by the denominator numerator denominator

  20. Write the fraction as a decimal .08 .375 .4 .45

  21. Changing a percent to a fraction • Write the percent in the numerator and 100 in the denominator. Simplify, if possible. EX: 78%

  22. Write the percent as a fraction 15% 75% 12% 7% 22% 46%

  23. Changing a percent to a decimal • Move the decimal point 2 places to the left EX: 76% .76

  24. Write as a DECIMAL .27 .17 27% 17% 6% 105% 8.3% 57.34% 5.64% 18.23% 8% 1.43% .06 10.5 .083 .5734 .0564 .1832 .08 .0143

  25. Changing a decimal to a percent • Move the decimal two places to the right • Write a percent sign EX: .389 38.9

  26. Write as a PERCENT 52% 2% .52 .02 .5 2 1.2 .25 20% 50% 25% 120%

  27. Write a fraction as a percent • Set up a percent proportion (equivalent fraction) OR divide the numerator by the denominator and move the decimal 2 places to the right. EX:

  28. Write as a PERCENT 60% 46% 90% 75%

  29. Application • If Suzanne answers 16 out of 20 questions correctly, what will her final percent grade be? 80%

  30. Application • 80% of Ms. Chokshi’s students ride the bus. What FRACTION of the class does NOT ride the bus?

  31. Percent of *Change the percent to a decimal *Change of to multiply *Multiply EX: 25% of 15 (.25)(15) 3.75

  32. (.42)(50) 21 (.09)(25) 2.25 42% of 50 9% of 25 12% of 33 7% of 75 (.12)(33) 3.96 (.07)(75) 5.25

  33. (.43)(65) 27.95 7% of 23 43% of 65 (.07)(23) 1.61 5% of 43 25% of 56 (.05)(43) 2.15 (.25)(56) 14

  34. Discount • Find the “percent of the original price”. • To find the sale price, subtract the discount from the original price. EX: 15% off of a $35 shirt (.15)(35) 5.25 (discount) 35 – 5.25 = $29.75 $29.75

  35. Discount 30% off of a $75 pair of shoes What is the discount? (.3)(75) 22.5 discount What is the sales price? 75 – 22.5 = 52.50 $52.50

  36. Discount 10% off of a $29.99 Wii game What is the discount? (.10)(29.99) 2.99 discount What is the sale price? 29.99 – 2.99 = $27 $27

  37. Tax • Find the “percent of the original cost” • To find the total cost: add the tax to the original cost of the item. EX: 6% sales tax on a Target bill of $75.23 (.06)(75.23) $4.5138 = 4.15 sales tax 75.23 + 4.15 = $79.38 $79.38

  38. Tax A snowboard costs $475. What would be 6% tax? (.06)(475) $28.5 What is the total cost of the snowboard, after tax? 475 + 28.5 $503.50

  39. Tax A book costs $21.49 How much is 6% sales tax? (.06)(21.49) 1.2894 = 1.29 sales tax What is the total of the book, after tax? 21.49 + 1.29 $22.78

  40. Tip • Find the “percent of the bill” • To find the total bill: add the tip to the original bill. EX: Jamie’s family ordered pizza. The bill was $25.47. They want to tip the delivery person 15%. What is the total amount they will pay? (.15)(25.47) 3.8205 = $3.82 tip 25.47 + 3.82 = $29.29 $29.29

  41. Tip • Ron spent $13.50 on lunch. He wants to leave a 17% tip. What is the tip? 17% of 13.50 (.17)(13.50) 2.295 $2.30 tip What is the total amount that Ron spent on lunch? 13.50 + 2.30 = 15.80 $15.80

  42. Tip • Mrs. Skelton and her husband went out to dinner. The bill was $27.50 • The Skelton’s left a 20% tip. How much did they tip the server? 20% of $27.50 (.2)(27.50) $5.50 tip What was the total amount they spent on dinner? 5.50 + 27.50 = 33 $33

  43. Circle Graph – How many? • To find the percent – set up a “percent of” problem. EX: The answers of 25 students are shown on a circle graph. Eight percent of the students said their favorite color is blue. How many students like the color blue?

  44. How many people like green the best? (.37)(32) = 11.84 12 people • How many people like pink the best? (.25)(32) = 8 8 people • How many people like yellow the best? (.09)(32) = 2.88 3 people 32 people

  45. Circle Graph - degrees • To find the degrees – set up as percent of 360° EX: The answers of 25 students are shown on a circle graph. Eight percent of the students said their favorite color is blue. What would be the measurement of the blue section on the circle graph?

  46. How many degrees is the green section? (.37)(360) = 133.2 133° • How many degrees is the red section? (.16)(360) = 57.6 58° • How many degrees is the purple section? (.09)(360) = 32.4 32° 32 people

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