如图,
中,
为
的中点,
是
上一点,连接
并延长交
于
,
,且
,
,求
的长度是多少?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7595bdaea3dfa548c0fcfe3708387476.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61e5b8523e99c8b73621cb1664cfb592.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56512504254ab7f574a717dd6830fb33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/8/a112c257-2cdc-4d6e-aa02-70391d2f31ef.png?resizew=215)
更新时间:2023-02-06 20:20:14
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】【发现问题】(1)数学活动课上,王老师提出了如下问题:如图1,在
中,
,
,求
边上的中线
的取值范围.
【探究方法】第一小组经过合作交流,得到了如下的解决方法:
①延长
到E,使得
;
②连接
,通过三角形全等把
、
、
转化在
中;
③利用三角形的三边关系可得
的取值范围为
,从而得到
的取值范围是______.
方法总结:解题时,条件中若出现“中点”、“中线”字样,可以考虑倍长中线构造全等三角形,把分散的已知条件和所求证的结论集合到同一个三角形中.
【问题解决】
(2)如图2,
是
的中线,
是
的中线,且
,
,下列四个选项中:直接写出所有正确选项的序号是______.
①
②
③
④![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e30e50e094cd2849e38859b36aad0b0c.png)
【问题拓展】
(3)如图3,
,
,
与
互补,连接
、
,E是
的中点,求证:
.
(4)如图4,在(3)的条件下,若
,延长
交
于点F,
,
,则
的面积是______.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a88d4e0249bd16d48eda01331d2d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8a7b5adfcac0f46a4cd19da4ebb4a2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/15/21a536b2-930b-47b5-86b2-eb957738e059.png?resizew=365)
【探究方法】第一小组经过合作交流,得到了如下的解决方法:
①延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ad98ad714864041a632ca949308e417.png)
②连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e97392ff60fac8a261c6eab71bba028b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
③利用三角形的三边关系可得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be4f7432b824c434b0a733ff9401c33e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
方法总结:解题时,条件中若出现“中点”、“中线”字样,可以考虑倍长中线构造全等三角形,把分散的已知条件和所求证的结论集合到同一个三角形中.
【问题解决】
(2)如图2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7ac5396c5ea442e0364b50c1db3d2da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bba0db442bddfa899bc89e15459e58e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91aa309697c5aefc87bd0b14dafe14d6.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa9e3f95ad200eb0abeb1cd67133628c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03ff4152c3e5998ae8e0ed8641f898bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b26656dce1b664fdbc1b207ee4ead267.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e30e50e094cd2849e38859b36aad0b0c.png)
【问题拓展】
(3)如图3,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fca3734de79f7f50b552ef62b29dc7c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33cbad6599796efc1c177ae9349feda9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d7b2fe01a33c4825f9974ed9663a99c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed66570f697459aba9daa2eaf9460bcb.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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/454b6221d931d7b0166d296bbcc5c315.png)
(4)如图4,在(3)的条件下,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20ccc37b189fa2cbc269ca0b233dac37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f90c780dac29ff8b7df5881d3b33abab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af50cf2832f5f794166ea50dc1cd4964.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48813b8fc61cdb0c54fbc6a2e4bbd30b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bbf9680f74a9ac5d934304654ce2771.png)
您最近一年使用:0次
解答题-证明题
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适中
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【推荐2】如图,在正方形ABCD中,点E、F分别在边BC、CD上,且∠EAF=45°,
(1)求证:BE+DF=EF;
(2)若BE=3,DF=2,求AB的长;
(1)求证:BE+DF=EF;
(2)若BE=3,DF=2,求AB的长;
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/16/c402e10b-b7f2-465e-8fc2-bea542c7e471.png?resizew=127)
您最近一年使用:0次
解答题-证明题
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【推荐1】如图,在平面直角坐标系中,点
的坐标为
,点
在第一象限,
,点
是
上一点,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/7/6b6d1b8f-8b30-4084-af6d-48c2584b8e65.png?resizew=146)
(1)求证:
;
(2)求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0aa18c4527e9ff4ee2ab1c4a8c3d5c24.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd3974d516c9252a00555f01952f7b1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85bdcc2742be52cc80ba7dbe79f9a574.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9a950167d57097085d189152a5fa2dd.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/7/6b6d1b8f-8b30-4084-af6d-48c2584b8e65.png?resizew=146)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c812c5c56113420cf7b235a3b055132a.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69f519a757c37be0f7071bb83d5032dc.png)
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解答题-证明题
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【推荐2】如图,在▱ABCD中,AD=2AB,F是AD的中点,CE⊥AB,垂足E在线段AB上,连接EF,CF.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/15/88325dff-2485-4265-9186-a94e1d39d436.png?resizew=296)
(1)求证:EF=CF;
(2)若S▱ABCD=9,BE=2AE,求△BEC的面积.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/15/88325dff-2485-4265-9186-a94e1d39d436.png?resizew=296)
(1)求证:EF=CF;
(2)若S▱ABCD=9,BE=2AE,求△BEC的面积.
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