如图,把矩形ABCD沿AC折叠,使点D与点E重合,AE交BC于点F,过点E作EG//CD交AC于点G,交CF于点H,连接DG.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/18/8eb3e473-5eb5-4a46-87d6-9f02b81b8ed2.png?resizew=129)
(1)求证:四边形ECDG是菱形;
(2)若
cm,
cm,求AC的长.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/18/8eb3e473-5eb5-4a46-87d6-9f02b81b8ed2.png?resizew=129)
(1)求证:四边形ECDG是菱形;
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60d1cbd48054865bf9b26712853e10c8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecd0783348827a3e049026ee2fbc1ea8.png)
更新时间:2021-11-13 16:11:07
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相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图,点E是矩形
的边
延长线上一点,连接
、
,
交
于点G,过点C作
交
于点F,
.求证:四边形
是菱形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21037e170bdbb322558e79c40c00b454.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fc56c77464a17a1e97b568762a3e2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fc56c77464a17a1e97b568762a3e2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b276efd97e4e83f79e86ab274bbd43ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d831c9ba6d18774540e2aaa29132fec9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32c05247f6998d7a70d31d13be4148c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/17/a7924339-9c3c-4c6e-a5f0-cf47530f85f1.png?resizew=130)
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解答题-作图题
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适中
(0.65)
【推荐2】如图,
为等边三角形.
求作:菱形
,使得
.
作法:如图,
①作
的平分线
,交
于点D;
②以点A为圆心,
长为半径画弧交
的延长线于点E;
③分别以点B,E为圆心,
长为半径画弧,两弧交于点F(不是点A);
④连接
.
则四边形
为所求作的菱形.
(1)使用直尺和圆规,依作法补全图形(保留作图痕迹);
(2)完成下面的证明.
证明:∵
,
∴四边形
为菱形(______)(填推理依据).
∵
为等边三角形,∴
.
∵
平分
,∴
______
.
∵
,∴
______
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
求作:菱形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/369eb8ad56da7dc1cdb7c43762be4bee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69a05312797f53571fb99d8e0f9e1075.png)
作法:如图,
①作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
②以点A为圆心,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67d822262ff00915910e5b87d81ad1ba.png)
③分别以点B,E为圆心,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
④连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5912e3dd19cd8024dfb950bad0358a11.png)
则四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/369eb8ad56da7dc1cdb7c43762be4bee.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/13/ee0d155f-b56a-496e-9261-7eccafb05f21.png?resizew=164)
(1)使用直尺和圆规,依作法补全图形(保留作图痕迹);
(2)完成下面的证明.
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d59410a590b4053f859f3d4732ca71b.png)
∴四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/369eb8ad56da7dc1cdb7c43762be4bee.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b57fdd2a3642716fcf5100011eb3ec88.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b495182bfde8f866fae490fdf0000393.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83873a9d782f2588c5eedbfe73f9bc2f.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee06e20972dffda43fd35f37953b2c3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4af17b55fa474f0103a858c2604b093.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83873a9d782f2588c5eedbfe73f9bc2f.png)
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【推荐3】学习了特殊平行四边形的相关知识后,小美进行深入探究,计划在已知矩形中构造出一个菱形,她的解决思路是通过作角相等和线段相等得到想要的菱形.请根据她的思路完成以下作图与填空:
(1)用直尺和圆规,在矩形
中,在
的下方作
,交边
于点
;再作
,交边
于点
,连接
.(保留作图痕迹,不写作法)
(2)在(1)所作的图形中,证明:四边形
是菱形.
四边形
是矩形
,
,
,
,
① ,
,
,
② ,
由矩形的性质知
,
,
在
和
中,
,
,
③ ,
,
,
四边形
是平行四边形,
,
四边形
为菱形( ④ )
(1)用直尺和圆规,在矩形
![](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/56845dd65a45ec0fa19df8d4af261511.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cf36322778b851e00806cd3c73db972.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/167d31eb8432b5c0364316e5048c23dd.png)
(2)在(1)所作的图形中,证明:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b977f9880c3acc912c36aa3e2df56c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f3d198e76391779fa3badc848c8ac8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e8644afba5451902a1d517ec584877a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8d2530e7023b2345c651e8f53629ff1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e246215bcc318864a10eb48d60634d61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f294a352a632d548e66521c240c19c05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb421664a7e00dea48d4c983b71e969d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f423de2c0e08063dca69ae1ee51b6b0f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
由矩形的性质知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c220eadc312101e2fb89dfe920f7b30d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59281d3136f2c67c078d98842171224d.png)
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5ebc9a7a29f686f4288c70391897b07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/375cdd3243f9ab1e44ca276212c31e57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f72b15c1fe7491000c54a637c1e14eaf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faae0131bacc6c6017573f81e1c7b5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c88d87a9ddad325ea3f05cb85ab0ee85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/777a0a78baa408e9e2a8ecf104299371.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b977f9880c3acc912c36aa3e2df56c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/004e4f9a78a4e831b12f055499f93b67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b977f9880c3acc912c36aa3e2df56c9.png)
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解答题-证明题
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适中
(0.65)
【推荐1】如图,在
中,
,D是
的中点,以
为直径的⊙O分别交
,
,
边于点G,F,E.
![](https://img.xkw.com/dksih/QBM/2021/5/5/2714337755324416/2715143869726720/STEM/fa44bdf2fa664becbdab66ed7c9c77fb.png?resizew=238)
(1)连结
,求证:
.
(2)连结
,当
时,求⊙O的直径长.
![](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/f52a58fbaf4fea03567e88a9f0f6e37e.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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/2021/5/5/2714337755324416/2715143869726720/STEM/fa44bdf2fa664becbdab66ed7c9c77fb.png?resizew=238)
(1)连结
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/058f36d315245b63a811d5c6f348c17b.png)
(2)连结
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb289e704d2aa5113706df24cf9d82d9.png)
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解答题-证明题
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【推荐2】如图是钉板示意图,相邻的两个钉点是边长为1个单位长的小正方形顶点,钉点A、B的连线与钉点C、D的连线交于点E.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/23/44d0d44d-643f-4d55-9580-da30ab504eea.png?resizew=105)
(1)求证:
;
(2)
______.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/23/44d0d44d-643f-4d55-9580-da30ab504eea.png?resizew=105)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a77e3c1c236141d6118429fade0a9b9d.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5277fa450a0c513a86a74420f8ee99f6.png)
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