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如图,C是⊙O上一点,若圆周角∠ACB=40°,则圆心角∠AOB的度数是( ) ...
如图,C是⊙O上一点,若圆周角∠ACB=40°,则圆心角∠AOB的度数是( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103100835090569512/SYS201311031008350905695029_ST/images0.png)
A.50°
B.60°
C.80°
D.90°
考点分析:
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观察图1-图4相应推理,其中正确的是( )
A.
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