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如图是一个零件示意图,A、B、C处都是直角,是圆心角为90°的弧,其大小尺寸如图...
如图是一个零件示意图,A、B、C处都是直角,
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103102418005047809/SYS201311031024180050478006_ST/0.png)
是圆心角为90°的弧,其大小尺寸如图标示.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103102418005047809/SYS201311031024180050478006_ST/1.png)
的长是( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103102418005047809/SYS201311031024180050478006_ST/images2.png)
A.π
B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103102418005047809/SYS201311031024180050478006_ST/2.png)
π
C.2π
D.4π
考点分析:
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