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如图,PB为圆O的切线,B为切点,连接PO交圆O于点A,PA=2,PO=5,则P...
如图,PB为圆O的切线,B为切点,连接PO交圆O于点A,PA=2,PO=5,则PB的长为( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103100850430783921/SYS201311031008504307839024_ST/images0.png)
A.4
B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103100850430783921/SYS201311031008504307839024_ST/0.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103100850430783921/SYS201311031008504307839024_ST/1.png)
D.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103100850430783921/SYS201311031008504307839024_ST/2.png)
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