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Chapter 7.1 and 7.7

Chapter 7.1 and 7.7. Ratios and Proportions and Scale Models and Drawings. Ratio – a comparison of two quantities using division Proportion – an equation stating that two ratios are equal. Definitions. Write and Simplify Ratios.

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Chapter 7.1 and 7.7

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  1. Chapter 7.1 and 7.7 Ratios and Proportions and Scale Models and Drawings

  2. Ratio – a comparison of two quantities using division • Proportion – an equation stating that two ratios are equal Definitions

  3. Write and Simplify Ratios SCHOOL The number of students who participate in sports programs at Central High School is 520. The total number of students in the school is 1850. Find the athlete-to-student ratio to the nearest tenth. To find this ratio, divide the number of athletes by the total number of students. Answer: The athlete-to-student ratio is 0.3.

  4. The country with the longest school year is China, with 251 days. Find the ratio of school days to total days in a year for China to the nearest tenth. (Use 365 as the number of days in a year.) A. 0.3 B. 0.5 C. 0.7 D. 0.8

  5. Use Extended Ratios In ΔEFG, the ratio of the measures of the angles is 5:12:13. Find the measures of the angles.

  6. The ratios of the angles in ΔABC is 3:5:7. Find the measure of the angles. A. 30, 50, 70 B. 36, 60, 84 C. 45, 60, 75 D. 54, 90, 126

  7. Concept

  8. Use Cross Products to Solve Proportions Answer:y = 27.3

  9. Use Cross Products to Solve Proportions B.

  10. A. A.b = 0.65 B.b = 4.5 C.b = –14.5 D.b = 147

  11. B. A.n = 9 B.n = 8.9 C.n = 3 D.n = 1.8

  12. Use Proportions to Make Predictions PETS Hima randomly surveyed 30 students from her class and found that 18 had a dog or a cat for a pet. If there are 870 students in Hima’s school, predict the total number of students with a dog or a cat.

  13. Suppose we are having a class party and Jess volunteers to bring guacamole. She has recipe that uses 4 avocadoes to make 10 servings. How many avocadoes does she need to make 25 servings? Recipes

  14. A scale model or a scale drawing is an object or drawing with lengths proportional to the object it represents. The scale of a model or drawing is the ratio of a length to the model or drawing to the actual length of the object being modeled or drawn. Scale Models and Drawings

  15. Use a Scale Drawing MAPS The distance between Boston and Chicago on a map is 9 inches. If the scale of the map is 1 inch: 95 miles, what is the actual distance from Boston to Chicago?

  16. MAPSThe distance between Cheyenne, WY, and Tulsa, OK, on a map is 8 inches. If the scale of the map is 1 inch : 90 miles, what is the actual distance from Cheyenne to Tulsa? A. 800 miles B. 900 miles C. 630 miles D. 720 miles

  17. Find the Scale A. SCALE MODEL A miniature replica of a fighter jet is 4 inches long. The actual length of the jet is 12.8 yards. What is the scale of the model? Answer: The scale of the model is 1 in. : 3.2 yd.

  18. Find the Scale B. SCALE MODEL A miniature replica of a fighter jet is 4 inches long. The actual length of the jet is 12.8 yards. How many times as long as the actual is the model jet? Answer: The scale factor is 115.2 : 1. That is, the actual jet is 115.2 times as long as the model.

  19. A. SCALE MODELA miniature replica of a fire engine is 9 inches long. The actual length of the fire engine is 13.5 yards. What is the scale of the replica? A. 2 in. : 3 yd B. 1 in. : 3 yd C. 2 in. : 5 yd D. 3 in. : 4 yd

  20. B. SCALE MODELA miniature replica of a fire engine is 9 inches long. The actual length of the fire engine is 13.5 yards. How many times as long as the model is the actual fire engine? A. 48 B. 54 C. 60 D. 63

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