1 . 如图所示,在⊙O中,相交于点E的两弦AB,CD的中点分别是M,N,直线MO与直线CD相交于点F.证明
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/26/cdcc2cdf-e541-42c8-bbce-48c05d3a473d.png?resizew=240)
(1)∠MEN+∠NOM=180°;
(2)FE·FN=FM·FO.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/26/cdcc2cdf-e541-42c8-bbce-48c05d3a473d.png?resizew=240)
(1)∠MEN+∠NOM=180°;
(2)FE·FN=FM·FO.
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2 . 如图所示,PA与圆O相切于点A,不过圆心O的割线PCB与直径AE相交于D点.已知∠BPA=30°,AD=2,PC=1,则圆O的半径等于________ .
![](https://img.xkw.com/dksih/QBM/2017/8/14/1758200027602944/1817081830203392/STEM/91b436abd3534b12b4bbcc4893490293.png?resizew=87)
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3 . 如图所示,AB是半圆O的直径,点C在半圆上,CD⊥AB于点D,且AD=3DB,设∠COD=θ,则tan2
=__ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a16d92d3ccdf0ecfaa43eb8ed62ae5a4.png)
![](https://img.xkw.com/dksih/QBM/2017/8/14/1758200027602944/1817081830195200/STEM/027e6e38fed14b0d94131d2fd983e44c.png?resizew=107)
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4 . 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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5 . 如图所示,
是
的直径,弦
于点
,
,
,求
的半径.
![](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/2017/1/25/1619472216219648/1619472216875008/STEM/8c5e1512409342fd97d6cdab7af57e45.png)
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6 . 如图所示,过圆
外一点
作它的一条切线,切点为
,过
点作直线
垂直于直线
,垂足为
.
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216842240/STEM/1da16b8163464d088175e61cd5d8bb4a.png)
(1)证明:
;
(2)
为线段
上一点,直线
垂直于直线
,且交圆
于
点.过
点的切线交直线
于
.证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3369e0ea90e8d5cf4b6b3c45c0fd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216842240/STEM/1da16b8163464d088175e61cd5d8bb4a.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acee1b8f3bb4a294b4cc67154688304f.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/279563c3c055777ce1aa369a2ef54aed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88e9f7d1272b7344346b58b660aa260a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88e9f7d1272b7344346b58b660aa260a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5f52ef170c9bebf83641eaa4b406b69.png)
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7 . 如图所示,
为
的直径,
,
是
的半径,
,点
在
上,
,点
是
上一动点,则
的最小值为 ________ .
![](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/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/828628c0876b45381c9a0edeb0fec236.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/771b610e4ddefa739a985d1e5462ce5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/667349d99185bb045030b733352ff7fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0183ed5a6ea476f7a7db1f8b5d9fad2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/828628c0876b45381c9a0edeb0fec236.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f320075cb747d3a747bb6dd87c4814.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216621056/STEM/c62ee430f5e34ff1b8cac53284bd0d2d.png?resizew=100)
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8 . 已知
和
内一点
,过
的直线交
于
两点,若
,
,则
的半径长为_________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e52586ca2a3b783bc8092415e2d4bf6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d41c053fd14095b09dab9e32262e69bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd7d518694c5ebd73d9bbf45b6b51e77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216596480/STEM/05ebc8de7cd4494fb7fa181588b6d870.png?resizew=105)
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9 . 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.![]() |
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10 . 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 |
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