1. Areas of Circles and Sectors
May 9, 2003
Areas of Circles and Sectors
GEOMETRY LESSON 7-7
Pages Exercises m2
cm2
ft2
in.2
5. about 86,394 ft2
6. about 22 ft2
yd2
cm2 9 m2
in.2
ft2
cm2 m2
ft2
in.2
cm2
169 6 25 4 3 2
cm2
ft2 m2 m2
cm3
22. ( ) ft2
23. ( ) cm2
24. ( ) m2
7-7

2. 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 – ) 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 in.2.
30. 9 circles
in.2
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 – 50;
35. (49 – ) m2
36. (200 – 50 ) m2 m2
7-7

3. 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.
– 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 – m2
[1] no work shown cm m
in.
in., 11 in., 11 in.,
15 in. 2
• 22
7-7

4. 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