问题
选择题
若一圆锥的底面半径为2，母线长为4，则其侧面展开图的圆心角是（ ）
A．120°
B．150°
C．180°
D．216°
答案
设圆锥侧面展开图的圆心角为n．
=2π×2，nπ×4 180
解得n=180°．
故选C．
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若一圆锥的底面半径为2，母线长为4，则其侧面展开图的圆心角是（ ）
A．120°
B．150°
C．180°
D．216°
设圆锥侧面展开图的圆心角为n．
=2π×2，nπ×4 180
解得n=180°．
故选C．
| 阅读理解。 | ||||
CCTV PROGRAMMES 中央电视台节目单
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| 1. If you want to watch a football game, the best program tor you would be "_____". | ||||
| A. TV play B.Sports C. Around the world D. Talk show | ||||
| 2. The program of "_____" will let you know much about western (西方的) countries. | ||||
| A. Sisters B. Around China C. Around the world D. On TV next week 3. If you want to know something about tigers elephants and monkeys, the best program for you is "_____". | ||||
| A. Around China B. Animal world C. TV play D. Foreign arts | ||||
| 4. English classroom is a program that _____. | ||||
| A. lets you know something about classroom B. tells you something about students C. tells you something about school life D. teaches you English | ||||
| 5. The program at the end of Channel 2 means (意思是) _____ on TV next week. | ||||
| A. news B. programs C. people D. places |