Areas of Circles and Sectors May 9, 2003 Areas of Circles and Sectors GEOMETRY LESSON 7-7 Pages 397-400 Exercises 1. 9 m2 2. 30.25 cm2 3. 0.7225 ft2 4. in.2 5. about 86,394 ft2 6. about 22 ft2 7. 40.5 yd2 8. 64 cm2 9 9. m2 10. 12 in.2 11. 12 ft2 12. 56 cm2 13. m2 14. ft2 15. 24 in.2 16. 28.125 cm2 169 6 25 4 3 2 17. 22.1 cm2 18. 18.3 ft2 19. 3.3 m2 20. 20.4 m2 21. 120.4 cm3 22. (243 + 162) ft2 23. (54 + 20.25 3 ) cm2 24. (120 + 36 3 ) m2 7-7

Areas of Circles and Sectors May 9, 2003 Areas of Circles and Sectors GEOMETRY LESSON 7-7 25. (4 – ) ft2 26. (64 – 16 ) ft2 27. (784 – 196 ) in.2 28. 11,310 ft2 29. Lower outside; the lower inside and top pieces have base areas 8 in.2, but the lower outside pieces have base areas 8.75 in.2. 30. 9 circles 31. 15.7 in.2 32. 12 in. 33. Answers may vary. Sample: 8 cm radius; 90° arc 34. a. Answers may vary. Sample: Subtract the minor arc segment area from the area of the circle, or add the areas of the major sector and formed. b. 25 – 50; 75 + 50 35. (49 – 73.5 3 ) m2 36. (200 – 50 ) m2 37. 4 m2 7-7

Areas of Circles and Sectors May 9, 2003 Areas of Circles and Sectors GEOMETRY LESSON 7-7 38. Blue region; let AB = 2x. Area of blue = 4x2 – x2; area of yellow = x2 – 2x2. 39. – 50 3 units2 40. a. 200 3 40. (continued) b. Find the area of of a circle of radius 10 and add of a circle of radius 2. c. 239 ft2 41. A 42. G 4 1 43. [2] area of rectangle = 2 • 12 = 24; area of semicircles = 3 • = 6 ; 24 – 6 5.2 m2 [1] no work shown 44. 10 cm 45. 2 m 46. 28 in. 47. 11 in., 11 in., 11 in., 15 in. 2 • 22 7-7

Areas of Circles and Sectors May 9, 2003 Areas of Circles and Sectors GEOMETRY LESSON 7-7 48. Show that BCE ACD by ASA. Then use CE CD and segment subtraction to show that BD AE. Now with vertical BFD AFE, BDF AEF by ASA. s 7-7