航空兵空投救灾物资到指定的区域(大圆)如图所示,若要使空投物资落在中心区域(小圆)的概率为
,则小圆与大圆半径的比值为( )
![](https://img.xkw.com/dksih/QBM/2015/3/5/1573807705292800/1573807711379456/STEM/35bdfefb55334fb29b8587dda1d39ac3.png)
![](https://img.xkw.com/dksih/QBM/2015/3/5/1573807705292800/1573807711379456/STEM/271261b04eb94261813ee979d7ba87fe.png)
![](https://img.xkw.com/dksih/QBM/2015/3/5/1573807705292800/1573807711379456/STEM/35bdfefb55334fb29b8587dda1d39ac3.png)
A.![]() | B.4 | C.![]() | D.2 |
更新时间:2015-03-05 15:23:45
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【知识点】 概率
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