如图,点D、E分别是△ABC的边AB、AC的中点,连接BE,过点C作CF∥BE,交DE的延长线于点F,若DE=1,求DF的长.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/30/c8e2e917-9c39-47f9-8db7-f996a32d26bb.png?resizew=112)
更新时间:2021-08-19 19:40:18
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相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在菱形
中,对角线
,
交于点O,过点A作
的垂线,垂足为点E,延长
到点F,使
,连接
.
(1)求证:四边形
是矩形;
(2)若菱形
的周长为
,
,求点A到
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a2a893fc8b2e9d55c9cdf8aceb3827a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/5/9c883717-fbf3-42fe-b1f4-4498a192730b.jpg?resizew=124)
(1)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/946c16d99496d31ce4d87301a4793393.png)
(2)若菱形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b72ac611ae66b86761e080761d9aabc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b707c3d2dcf2f53fea4ef045dd8f295.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
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名校
【推荐2】如图,四边形
是平行四边形,
相交于点O,点E是
的中点,连接
,过点E作
于点F,过点O作
于点G.
是矩形;
(2)若四边形
是菱形,
,
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d578394cd8e4d7a705599269c512960.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a299d2b999568e80be8005565ba209a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc90fee532e50d319081d571410421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbdaf6769ca790186718cc60c7b89ba6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f690b762b0e0410d1757e620434f89be.png)
(2)若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f08273d339dc5ddbb89aa67bb8205e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d71e6ea7333dbc78d0a7b9bc3892f940.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
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解答题-证明题
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适中
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名校
【推荐1】如图,矩形 ABCD 中,点 E、F 分别在边AD、BC上,直线EF垂直平分对角线AC,垂足为点 O,M、N 分别为线段 EC、OC 的中点.
(1)求证:四边形EAFC是菱形.
(2)若AB=4,DA=8,则tan∠MAN= .
(1)求证:四边形EAFC是菱形.
(2)若AB=4,DA=8,则tan∠MAN= .
![](https://img.xkw.com/dksih/QBM/2021/6/12/2741156602888192/2796048590282752/STEM/bf143914-eb8c-4a7a-b2dd-ec16f6767e44.png?resizew=126)
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解答题-问答题
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适中
(0.65)
【推荐2】如图,在
中,
,
分别是
的中点,延长
到点
,使得
,连接
与
交于点
.
,求四边形
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/421456e82c859184328587723f85034d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd6877751384616819a8ddeef96c4133.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cb83b580d11e18af554f23054c60cf9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06affe04ec36fb5ddfec349c746d3bc1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c12dcfd3f1f0581316814e3446eceb89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/946c16d99496d31ce4d87301a4793393.png)
![](https://img.xkw.com/dksih/QBM/2023/1/31/3164553625550848/3164806906011648/STEM/28ceac6392f64572bd2216eb7df4c1f5.png?resizew=197)
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解答题-证明题
|
适中
(0.65)
【推荐3】【探究与证明】如图,在四边形
中,对角线
与
相交于点O,记
的面积为
,
的面积为
.
,求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad3682afa5e3e71971c82d35c98a6146.png)
小红同学展示出如下正确的证明办法,请在横线上将内容补充完整.
证明:过点D作
交
于点E,过点B作
交
于点F,如图①所示:则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91d56a03d21943559c3ec5d01beed973.png)
∴
____________
(填写位置关系)
∴
____________;
∴
____________;
∵
;
;
∴
.
(2)【探索推广】如图②,若
与
不平行,(1)中的结论是否成立?若成立,请证明;若不成立,请说明理由.
(3)【拓展应用】如图③,在
上取一点
,使
.过点
作
交
于点
,点
为
的中点,
交
于点
,且
,若
,求
值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/3a9a6eeeebf3cff569578d7366b755aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/866b81a8384cce4f24867baca2e6820c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a11029ca6b4b9e7f777af0280cf163c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad3682afa5e3e71971c82d35c98a6146.png)
小红同学展示出如下正确的证明办法,请在横线上将内容补充完整.
证明:过点D作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68fbbd17c89f03dbb61cd6ffdb9a0344.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f2a245381e615882ee5feb7793a1df6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91d56a03d21943559c3ec5d01beed973.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b06ed283116db8ab2a1a254724226175.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48acf06b38de34c9d3d9562712b0a0ec.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9e49d7d94bdef2c89cd1bd2992e43d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a919108801acc6b42f99dbf223e4475e.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17bb6a453a3ccba3c36269b1b2e60240.png)
(2)【探索推广】如图②,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(3)【拓展应用】如图③,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb43a62f3bfd7666ab898bcb5efc1ec4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c41158715d94c6c9ffebdee957d2618.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/683c590673eece14fea3319c4fd5eb55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c4cd68cc82e90a5e2049a7ea3171b84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8d51083cf65d74e2856c9755c1ebaa0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af28f52ccef42710bfb647db4f2f0f53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/235f0a6fb218d28383e6f27f2df1f50f.png)
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