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圆 周 角( 1 )

圆 周 角( 1 ). 常州市勤业中学 高煜. P. 问题 1. 问题 2. 1. 3. 2. A. B. C. 5.3 圆周角. 定义: 顶点在圆上,两边都和圆相交的角叫做圆周角。. 练一练:. 1 、下列各图中,哪一个角是圆周角?( ). B. P. 练一练:. 2 、图 3 中有几个圆周角?( ) ( A ) 2 个 ( B ) 3 个 ( C ) 4 个 ( D ) 5 个. C. 3 、写出图 4 中的圆周角:. ∠ A 、 ∠ C 、 ∠ B. 思考: BC 所对的圆心角有多少个?. BC 所对的圆周角有多少个?.

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圆 周 角( 1 )

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  1. 圆 周 角(1) 常州市勤业中学 高煜 www.themegallery.com

  2. P 问题1

  3. 问题2 1 3 2

  4. A B C

  5. 5.3 圆周角 定义:顶点在圆上,两边都和圆相交的角叫做圆周角。

  6. 练一练: 1、下列各图中,哪一个角是圆周角?( ) B

  7. P 练一练: 2、图3中有几个圆周角?( ) (A)2个 (B)3个 (C)4个 (D)5个 C 3、写出图4中的圆周角: . ∠A、 ∠C、 ∠B

  8. 思考:BC所对的圆心角有多少个? BC所对的圆周角有多少个? 操作: 由圆心和圆周角的不同的位置关系,请在图中画出BC所对的圆心角和圆周角。你能画出几种不同的图形? 猜想与探究

  9. 同弧或等弧所对的圆周角相等,都等于该弧所对的圆心角的一半.同弧或等弧所对的圆周角相等,都等于该弧所对的圆心角的一半.

  10. 1 3 2

  11. A B C

  12. 练一练: 4、如图6,已知∠ACB = 20º, 则∠AOB = , ∠OAB =. 40º 70º

  13. 练一练: 5、如图7,已知圆心角∠AOB=1000, 则∠ACB = . 130º

  14. 练一练: 6、 (1)在⊙O中,一条弧所对的圆心角是120°,该弧所对的圆周角是度; (2)在⊙O中,一条弦所对的圆心角是120°,该弦所对的圆周角是度.

  15. 例题讲解: 例1 例2

  16. 谢谢! www.themegallery.com

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