1 . 如图所示,⊙O是△ABC的外接圆,AD是⊙O的直径,连接CD,若⊙O的半径r=
,AC=2,则cos B的值是( )
![](https://img.xkw.com/dksih/QBM/2017/8/14/1758200027602944/1817081830154240/STEM/c15e7f13ca2b468897843317de4c17b0.png?resizew=84)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4b8503f4706b8321e4e79a87eadea84.png)
![](https://img.xkw.com/dksih/QBM/2017/8/14/1758200027602944/1817081830154240/STEM/c15e7f13ca2b468897843317de4c17b0.png?resizew=84)
A.![]() | B.![]() |
C.![]() | D.![]() |
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2 . 圆内两条相交弦长,其中一弦长为
,且被交点平分,另一条弦被交点分成1:4两部分,则这条弦长是
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216547328/STEM/ca527d0e42884f54a6c199234a973dd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af62da2f87dfc02c63e7a1c0949f09d6.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216547328/STEM/ca527d0e42884f54a6c199234a973dd0.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
3 . 如图,
切
于
,若
,
,
,
,则
等于
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216530944/STEM/98b7383142fd4af8bcf9b9cfaf56f6ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b1ec05e3cec27677ded7b4aecaa62d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b68df477b3ee45ac0f725db00d465a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07c56803859bab5c8f42c7e3b8279112.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86338536656046e93b53672ade9a78b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc11331a7b2d2619b40ee6d34c3bd620.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/377b5f7197e5bd1afeea4d931307956a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216530944/STEM/98b7383142fd4af8bcf9b9cfaf56f6ae.png)
A.3 | B.4 |
C.6 | D.8 |
您最近一年使用:0次
4 . 如图所示,
是
的直径,弦
于点
,
,
,那么
的半径是
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216383488/STEM/bcd15e6d98294583b6cdd0e6f142d64f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65b49c2d3750b2d5edf783374a51e481.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53e9da3d3086fc3673e3b136d4e6fc35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216383488/STEM/bcd15e6d98294583b6cdd0e6f142d64f.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
5 . 如图所示,已知
的半径为5,两弦
相交于
的中点
,且
,
,则圆心到弦
的距离为
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216309760/STEM/0dc3c8eae2084be882c3aad96e42d349.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c28d2790a97390935125aa897417f970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54275b7e571660d0a9e0370fbfe5050b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cd4f42b0c8c1b81c4f2a73bfa67b234.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216309760/STEM/0dc3c8eae2084be882c3aad96e42d349.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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