我们古代数学家擅长通过计算来研究图形的性质.例如《测圆海镜》卷中记载:“假令有圆城一所,不知周径.或问甲、乙二人同立于巽地,乙西行四十八步而立,甲北行九十步,望乙与城参相直,问径几何?”意思是:如图,
是直角三角形,
,已知
步,
步,
与
相切于点
分别与
相切于为点
,求
的半径.根据题意,
的半径是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/545ad5f3d39221f3390db9668f30257d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49f4c3d64ac2f0afd292bd0798d4ebd5.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/568a6fc66fdc6acf6701021f5a413c4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
A.100步 | B.120步 | C.140步 | D.160步 |
更新时间:2024-05-28 17:17:58
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【推荐1】如图,一个边长分别是6,8,10的直角三角形的一个顶点与正方形的点A重合,另两个顶点在正方形的两边
,
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【推荐2】若菱形的面积为120,其中一条对角线的长为10,则该菱形的周长为( )
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【推荐1】如图,边长为1的正方形
绕点A逆时针旋转
得到正方形
,连接
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的长是( )
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/23/f717839a-f3cb-4791-adb9-03a49a106d3e.png?resizew=100)
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【推荐2】如图,在
中,
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,
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的内切圆半径
长为( )
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/13/d9b1d67f-6658-4ae5-9203-c655df51f5da.png?resizew=160)
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【推荐1】如图,PA和PB是⊙O的两条切线,A,B为切点,点D在AB上,点E,F分别在线段PA和PB上,且AD=BF,BD=AE.若∠P=α,则∠EDF的度数为( )
![](https://img.xkw.com/dksih/QBM/2022/4/21/2962812440469504/2977130503208960/STEM/c9d9b3e0-fae5-4f75-a138-7cb2066a7995.png?resizew=360)
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【推荐2】如图,
,点
在边
上,
与边
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等于( )
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【推荐1】如图,△ABC中,∠C=90°,AC=12,BC=5,⊙O与△ABC的三边相切于点D、E、F,则AD长为( )
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【推荐2】如图,P为圆O外一点,
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