如图,
,直线m,n与a,b,c分别相交于点A,B,C和点D,E,F.若
,
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9bf0c66143cdb7b5f34e8b4e3a8b10e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0b47e74d3b400fae083c24768c95918.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ed650e192b6e94b4a99c05fb9ea93c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/9/a379234a-2601-48c6-8f47-ec5e6b10836f.png?resizew=157)
更新时间:2024-02-26 18:22:46
|
【知识点】 由平行截线求相关线段的长或比值解读
相似题推荐
解答题-问答题
|
较易
(0.85)
【推荐1】请阅读下面材料,并回答所提出的问题.
三角形内角平分线性质定理:三角形的内角平分线分对边所得的两条线段和这个角的两边对应成比例.
已知:如图,
中,
是角平分线,求证:
.
分析:在比例式
中,
恰是
、
、
的第四比例项,所以考虑过
作
,交
的延长线于
,从而得到
、
、
的第四比例项
,这样,证明
就可以转化成证明
.
AI
证明:如图,过
作
,交
的延长线于
,则
,
.
平分
,
,
,
,
,
,
.
(1)上述证明过程中,用到了哪些定理?(写对两个定理即可)
(2)在上述分析、证明过程中,主要用到了下面三种数学思想中的哪一种?选出一个填在后面的括号内(只填序号)( )
①数形结合思想;②转化思想;③分类讨论思想.
(3)用三角形内角平分线性质定理解答问题:
已知:如图,在
中,
是角平分线,
,
,
.求
的长.
三角形内角平分线性质定理:三角形的内角平分线分对边所得的两条线段和这个角的两边对应成比例.
已知:如图,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7adc97ebf4359db48dd4df96cc4d1b8.png)
分析:在比例式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7adc97ebf4359db48dd4df96cc4d1b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60f11e9afb1c3b15f364f2c95ca3a41d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7adc97ebf4359db48dd4df96cc4d1b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/934a9508c176f44bf58f88715bd98f76.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/27/394b5a43-50b5-4f8f-9805-481beff551b1.png?resizew=162)
证明:如图,过
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60f11e9afb1c3b15f364f2c95ca3a41d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97518125872037c6fa907c91f1bc6189.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba02910a01689f636c71116e96dfdf33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c574f339991ec2ff4e6697ed0012f851.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5ef0347b083bb3e9bebd969f49e459f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac38e3a230e86c4fedd006d10eb66878.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d745c2c6fc722616410728514ed896b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/542c6936504a16bdef14a4edaaf1ef43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bfb62671ba240b942581435c1ce43d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03602f432ccbe72aec99cf00b3208d3e.png)
(1)上述证明过程中,用到了哪些定理?(写对两个定理即可)
(2)在上述分析、证明过程中,主要用到了下面三种数学思想中的哪一种?选出一个填在后面的括号内(只填序号)( )
①数形结合思想;②转化思想;③分类讨论思想.
(3)用三角形内角平分线性质定理解答问题:
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/27/a409d8e9-118f-4a64-abca-c430e60a6436.png?resizew=136)
已知:如图,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6850a299395c314b8f8f2f8ca50c9895.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28f9fc63aeaac7f7e359f1bcd734a90f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57b276eec990e6edaae4bd27440dd3eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
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较易
(0.85)
名校
【推荐2】(1)如图,
,若
,
,求
的长.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/17/6f1bcbf1-c5fb-40da-8e52-442a9675fc43.png?resizew=167)
(2)下面是某同学解方程
的部分运算过程:
①该同学的解答从第______步开始出错;
②请写出正确的解答过程.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a120b008b7be40c9d6f6079bca61652.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ec2daeb3938525290d6683f72edd3f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6a028fd5b281ef168702a803baca6e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/17/6f1bcbf1-c5fb-40da-8e52-442a9675fc43.png?resizew=167)
(2)下面是某同学解方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e212a644e78b091254152e15f454e4d3.png)
解:移项,得![]() 配方,得 ![]() 即 ![]() 两边开平方,得 ![]() … |
②请写出正确的解答过程.
您最近一年使用:0次