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(2000•安徽)已知:如图,△ABC是⊙O的内接正三角形,弦EF经过BC的中点...
(2000•安徽)已知:如图,△ABC是⊙O的内接正三角形,弦EF经过BC的中点D,且EF∥AB,若AB=2,则DE的长是( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131021232717094869838/SYS201310212327170948698029_ST/images0.png)
A.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131021232717094869838/SYS201310212327170948698029_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131021232717094869838/SYS201310212327170948698029_ST/1.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131021232717094869838/SYS201310212327170948698029_ST/2.png)
D.1
考点分析:
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