1 . 如图所示,在正三角形
中,
分别在
上,且
,
,则有
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472519102464/1619472519249920/STEM/d52142abcce345a884f8ebfcd413cb60.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e1e4115d78e625e9e0f47cdade3286.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5881068127a39caf319492b4177204f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b7f4d3c66b40527658995411096d901.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c45087cde2d66377517a3fce5553b35.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472519102464/1619472519249920/STEM/d52142abcce345a884f8ebfcd413cb60.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
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2 . 若三角形的三条边之比为3:5:7,与它相似的三角形的最长边为
,则其余两边的长度之和为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c46dfb41bf21292ed4ba45d576148756.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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3 .
中,
,
,垂足为
.若
,
,则
长为
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472519102464/1619472519454720/STEM/8b0209d571444264bde61c0c775fd7d8.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472519102464/1619472519454720/STEM/8376401c404342628e9e9523fab5ae02.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472519102464/1619472519454720/STEM/a93307c0cf184cd5a5c45b62bed1fa6d.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472519102464/1619472519454720/STEM/2afb9963cea14c7eb24786f9a7918751.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472519102464/1619472519454720/STEM/75006e016ea24c22816ab8c40c73d181.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472519102464/1619472519454720/STEM/d1ccc189b8ed456ea68b3a36e6978f15.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472519102464/1619472519454720/STEM/c1ee1f118ffa49de96b21d88cbae417a.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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4 . 如图所示,已知
是圆心,直径
和弦
相交于点
,
,
,
,则
等于
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/3921ec3c590445baa52a1041fd79ab28.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/d078ad3c5e304917969a5aa2637fb94a.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/46a3f5efc0014ce6bf83a536bc3d05d9.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/0265cd0807b94ce28d417b8cee9202cf.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/32b78dd824ba4c139fdec2dbcf656d84.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/13a221a800c94202b39b9ed179bda3bb.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/5a8ad33512354a158f701b6ec772fa42.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/532c4f12fc4c4f66904c9f31d9674345.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/46a3f5efc0014ce6bf83a536bc3d05d9.png)
![](https://img.xkw.com/dksih/QBM/2017/1/25/1619472216219648/1619472216457216/STEM/3921ec3c590445baa52a1041fd79ab28.png)
A.3 | B.8 |
C.12 | D.14 |
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12-13高三下·河北石家庄·阶段练习
5 . 选修4-1几何证明选讲
如图,AB是
O的直径,BE为圆0的切线,点c为
o 上不同于A、B的一点,AD为
的平分线,且分别与BC 交于H,与
O交于D,与BE交于E,连结BD、CD.
![](https://img.xkw.com/dksih/QBM/2013/3/15/1571143959781376/1571143965417472/STEM/b348fe291c244484bf89e15a5a8a6a2c.png)
(I )求证:BD平分![](https://img.xkw.com/dksih/QBM/2013/3/15/1571143959781376/1571143965417472/STEM/f54719e7f9d54dee90b65968e935b270.png)
(II)求证:AH•BH=AE•HC
如图,AB是
![](https://img.xkw.com/dksih/QBM/2013/3/15/1571143959781376/1571143965417472/STEM/8b43c3c3b2144703b527e83c122a5c2a.png)
![](https://img.xkw.com/dksih/QBM/2013/3/15/1571143959781376/1571143965417472/STEM/8b43c3c3b2144703b527e83c122a5c2a.png)
![](https://img.xkw.com/dksih/QBM/2013/3/15/1571143959781376/1571143965417472/STEM/2d4d4061425c45c6aaf748b93fc86366.png)
![](https://img.xkw.com/dksih/QBM/2013/3/15/1571143959781376/1571143965417472/STEM/8b43c3c3b2144703b527e83c122a5c2a.png)
![](https://img.xkw.com/dksih/QBM/2013/3/15/1571143959781376/1571143965417472/STEM/b348fe291c244484bf89e15a5a8a6a2c.png)
(I )求证:BD平分
![](https://img.xkw.com/dksih/QBM/2013/3/15/1571143959781376/1571143965417472/STEM/f54719e7f9d54dee90b65968e935b270.png)
(II)求证:AH•BH=AE•HC
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6 . 圆x2+y2-2x-1=0关于直线2x-y+3=0对称的圆的方程是
A.(x+3)2+(y+2)2=2 | B.(x+3)2+(y+2)2=![]() |
C.(x+3)2+(y-2)2=2 | D.(x+3)2+(y-2)2=![]() |
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