在
中,
,
,将
绕点
顺时针旋转一定的角度
得到
,点
,
的对应点分别是点
,
.
(1)当点
恰好在
上时,如图
.求
的大小;
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/25/e70551e5-acbe-4037-a675-98596364204b.png?resizew=124)
(2)若
时,点
是边
的中点,如图
.求证:四边形
是平行四边形;
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/25/ae94d8cb-b61b-4bdd-9dec-bc753d4b3c2a.png?resizew=134)
(3)当
时,连接
,
,设
的面积为
.在旋转过程中,
是否存在最大值?若存在,请直接写出
的最大值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/392b9e1a179a6676362679354a9e7e51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2689f0ce5ab3467d8214794d8acb2bd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
(1)当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23dc2d2dd56fcc67698c45a6e0e48f80.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/25/e70551e5-acbe-4037-a675-98596364204b.png?resizew=124)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97cf714ffb3fd5917a76b191640b55fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2330c01a4d2b5b20f106e3e48834d5c0.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/25/ae94d8cb-b61b-4bdd-9dec-bc753d4b3c2a.png?resizew=134)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
更新时间:2021-07-25 12:47:46
|
相似题推荐
解答题-问答题
|
较难
(0.4)
【推荐1】
与
均为等婹直角三角形,
.
,
,
在同一直线上时,
的延长线与
交于点
,则
______.
(2)当
与
的位置如图2时,
的延长线与
交于点
,猜想
的大小并证明你的结论.
(3)如图3,当A,
,
在同一直线上时(A,
在点
的异侧),
与
交于点
,
,请直接写出
,
,
之间的数量关系.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c15514bc735fe4b744672edefe00009c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86ae31b70c84b0c8bf215843182a8c66.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2db836f93d4f8641b991e0269efd8a8.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c15514bc735fe4b744672edefe00009c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97e152c7ab6ce9602ca73d5da3f0fa1d.png)
(3)如图3,当A,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fbf18a89d2bc8795a4393d02b0f970e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
您最近一年使用:0次
解答题-作图题
|
较难
(0.4)
【推荐2】综合与探究
某学校活动小组在作三角形的拓展图形,研究其性质时,经历了如下过程:
操作发现:
(1)已知,
,如图1,分别以
和
为边向
外侧作等边
和等边
,连接
.
,请你完成作图,并猜想
与
的数量关系是 .(要求:尺规作图,不写作法但保留作图痕迹)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/4/6688f5e1-9052-4817-ace7-1ed3f75d98be.png?resizew=150)
(2)类比探究:如图2,分别以
和
为边向
外侧作正方形
和正方形
,连接
.
,试猜想
与
之间的数量关系,并证明你的结论.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/4/579feb73-12c9-4c4c-a611-2a913e5c380f.png?resizew=200)
(3)拓展运用:如图3,已知
中,
,
,
,过点
作
,垂足为
,且满足
,求
的长.
某学校活动小组在作三角形的拓展图形,研究其性质时,经历了如下过程:
操作发现:
(1)已知,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3c65edad25ddd666cdce0d7e5afefc9.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/b3c65edad25ddd666cdce0d7e5afefc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80c505c02c59313fe0108392a5bf5127.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e6980abd7792294c0143eafb2b165e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/4/6688f5e1-9052-4817-ace7-1ed3f75d98be.png?resizew=150)
(2)类比探究:如图2,分别以
![](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/b3c65edad25ddd666cdce0d7e5afefc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad3a079cfdcca9acdacecbf08f9f78cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff7a0bfc593a8a33b6cade6ba213904c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/4/579feb73-12c9-4c4c-a611-2a913e5c380f.png?resizew=200)
(3)拓展运用:如图3,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3c65edad25ddd666cdce0d7e5afefc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c42ed2e5bd5a0f033e24008697bf4963.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080ca48cd27d4bf9d9ef084b558fc17a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f8eeeea1c9652cacce976f8129cf520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09e2132b711f5aa21a0048ad3fc37f16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06a2ab6940dca62be1f3b2b5f8531990.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://img.xkw.com/dksih/QBM/2022/5/12/2977926575210496/2987291877285888/STEM/479566d3-ae29-49c5-a2a5-f54f434f3ea9.png?resizew=154)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
解题方法
【推荐1】如图,在直角坐标系中,B(0,20),D(25,0),一次函数
的图象过C(40,n),与x轴交于A点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/4/452e0af9-a501-44c9-a5fd-d1c5029b3aad.png?resizew=206)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/4/efcb85a9-3783-411d-9d15-3ef0532e85cf.png?resizew=208)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/4/04b0211d-4a50-4e0c-a3d2-bd564388f1a4.png?resizew=208)
(1)求点A和点C坐标;
(2)求证:四边形ABCD为平行四边形;
(3)将△AOB绕点O顺时针旋转,旋转得△A1OB1,问:能否使以O、A1、D、B1为顶点的四边形是平行四边形?若能,求点A1的坐标;若不能,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/592908cd8387386a35aa7feee26b2007.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/4/452e0af9-a501-44c9-a5fd-d1c5029b3aad.png?resizew=206)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/4/efcb85a9-3783-411d-9d15-3ef0532e85cf.png?resizew=208)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/4/04b0211d-4a50-4e0c-a3d2-bd564388f1a4.png?resizew=208)
(1)求点A和点C坐标;
(2)求证:四边形ABCD为平行四边形;
(3)将△AOB绕点O顺时针旋转,旋转得△A1OB1,问:能否使以O、A1、D、B1为顶点的四边形是平行四边形?若能,求点A1的坐标;若不能,请说明理由.
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐2】如图1,在矩形
中,对角线
与
相交于点O,点E,F分别为
,
的中点,延长
至G,使
,连接
,
.
(1)求证:四边形
是平行四边形.
(2)如图2,若四边形
是菱形,求
的值.
![](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/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/683c590673eece14fea3319c4fd5eb55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/312c446a4790d75afde82f81e0e217ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
(1)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d819c261ee68e705e0d71815a050b7aa.png)
(2)如图2,若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d819c261ee68e705e0d71815a050b7aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8881d100ab0cb089b52aadfc6094bbe.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐3】综合与实践;
【问题情境】为了研究折纸过程中蕴涵的数学知识,老师发给每位同学完全相同的纸片,纸片形状如图1,在四边形
中(
),
,
.
【探究实践】
老师引导同学们在边
上任取一点E,连接
,将
沿
翻折,点C的对应点为H,然后将纸片展平,连接
并延长,分别交
,
于点M,G.老师让同学们探究:当点E在不同位置时,能有哪些发现?经过思考和讨论,小莹、小明向同学们分享了自己的发现.
(1)如图2,小莹发现:“当折痕
与
夹角为
时,则四边形
是平行四边形”.请你判断小莹的结论是否正确,并说明理由.
(2)如图3,小明发现:“当E是
的中点时,延长
交
于点N,连接
,则N是
的中点”,请你判断小明的结论是否正确,并说明理由.
【拓展应用】
(3)如图4,小慧在小明发现的基础上,经过进一步思考发现:“延长
交
于点F.当给出
和
的长时,就可以求出
的长”.老师肯定了小慧同学结论的正确性.若
,
,请你帮小慧求出
的长.
【问题情境】为了研究折纸过程中蕴涵的数学知识,老师发给每位同学完全相同的纸片,纸片形状如图1,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f609cdfc6f3a96264bd9f43873b1869b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60d9142db4dd2ef151bf3d4a63afb61e.png)
【探究实践】
老师引导同学们在边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a0acc93490a6a784eb62201d93dd93d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6655e2fa64a32cd12fe0279afd65d73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(1)如图2,小莹发现:“当折痕
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb78bddee5406ae514db9a1d0a903f0a.png)
(2)如图3,小明发现:“当E是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c4c865445dda4a59b6d5cb18fd74404.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
【拓展应用】
(3)如图4,小慧在小明发现的基础上,经过进一步思考发现:“延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/589786dd7c3a2679c3230b671cd232d6.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/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07160f14b3b453bebb64cb2bf96dc85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d64e0206b1814c35cc96bd2b6b12239a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
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解答题-证明题
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较难
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【推荐1】直角三角形有一个非常重要的性质:直角三角形斜边上的中线等于斜边的一半,比如:如图
,
中,
,
为斜边
中点,则
.请你利用该定理和以前学过的知识解决下列问题:
如图
,在
中,点
为
边中点,直线
绕顶点A旋转,若
、
在直线
的异侧,
直线
于点
,
直线
于点
,连接
、
;
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/18/6f42cce4-0379-4fb5-9461-5cb1c2b40dec.png?resizew=321)
(1)求证:
;
(2)若直线
绕点
旋转到图
的位置时,点
、
在直线
的同侧,其它条件不变,此时
还成立吗?若成立,请给予证明:若不成立,请说明理由;
(3)如图
,
,
旋转到与
垂直的位置,
为
上一点且
,
于
,连接
,取
中点
,连接
,
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e6a0f57f55b361f6985d5e7c8b25a59.png)
如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7767d492158189b23af332a8016ed37d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00c25c4259d935d6e6fabe5c3fc1f43c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/892909e49156f7dcc0650fcd65243877.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c8ffe24cf9f327aeb241225ab15ab1a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/18/6f42cce4-0379-4fb5-9461-5cb1c2b40dec.png?resizew=321)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4acd79bb9fb06f7c806eb6e17e4b613.png)
(2)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4acd79bb9fb06f7c806eb6e17e4b613.png)
(3)如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.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/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/934a9508c176f44bf58f88715bd98f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36477392f9aef13d69a098e1356d8a71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.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/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/892909e49156f7dcc0650fcd65243877.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c8ffe24cf9f327aeb241225ab15ab1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d3835e6398d18d162afebc92cd2ae9a.png)
您最近一年使用:0次
解答题-证明题
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较难
(0.4)
【推荐2】已知,在△ABC中,以△ABC的两边BC,AC为斜边向外测作Rt△BCD和Rt△ACE,使∠CAE=∠CBD,取△ABC边AB的中点M,连接ME,MD.
特例感知:
(1)如图1,若AC=BC,∠ACB=60°,∠CAE=∠CBD=45°,取AC,BC的中点F,G,连接MF,MG,EF,DG,则ME与MD的数量关系为______,∠EMD=______;
(2)如图2,若∠ACB=90°,∠CAE=∠CBD=60°,取AC,BC的中点F,G,连接MF,MG,EF,DG,请猜想ME与MD的数量关系以及∠EMD的度数,并给出证明;
类比探究:
(3)如图3,当△ABC是任意三角形,∠CAE=∠CBD=α时,连接DE,请猜想△DEM的形状以及∠EMD与α的数量关系,并说明理由.
特例感知:
(1)如图1,若AC=BC,∠ACB=60°,∠CAE=∠CBD=45°,取AC,BC的中点F,G,连接MF,MG,EF,DG,则ME与MD的数量关系为______,∠EMD=______;
(2)如图2,若∠ACB=90°,∠CAE=∠CBD=60°,取AC,BC的中点F,G,连接MF,MG,EF,DG,请猜想ME与MD的数量关系以及∠EMD的度数,并给出证明;
类比探究:
(3)如图3,当△ABC是任意三角形,∠CAE=∠CBD=α时,连接DE,请猜想△DEM的形状以及∠EMD与α的数量关系,并说明理由.
![](https://img.xkw.com/dksih/QBM/2019/5/25/2211450815414272/2212257167269888/STEM/e189884ee20a4734909062f3bacf54c8.png?resizew=471)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐1】在边长为8的等边三角形
中,D为
的中点,E,F分别为
、
上任意一点,连接
,将线段
绕点E顺时针旋转
得到线段
,连接
交
于点N,连接
.
(1)如图1,点E与点C重合,且
的延长线过点B,证明:四边形
是菱形;
(2)如图2,
的延长线交
于点M,当
时,求
的度数;
(3)如图3,E为
的中点,连接
,H为直线
上一动点,连接
,将
沿
翻折至
所在平面内,得到
,连接
,直接写出线段
长度的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/6/4a9014d9-9cc4-4dd2-848b-dbd07b9eebec.png?resizew=533)
(1)如图1,点E与点C重合,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0e57a13c665af88f326c9890072bf73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0f875de8bec0ffc84b8142f81080058.png)
(2)如图2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10d20423901199473026f14e7b4797a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb04f507cc2eadbb5881f815d206d81e.png)
(3)如图3,E为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/589786dd7c3a2679c3230b671cd232d6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bc5c12b241539cc99487865f7d8bf34.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/589786dd7c3a2679c3230b671cd232d6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/601429eb4fcaef99f65d78ac38a3d28c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f85cd6c591dcb433a553fdc72fda9b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f85cd6c591dcb433a553fdc72fda9b3.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐2】问题提出:已知
,
,并且
与
完全重合在一起,将
绕点
顺时针方向旋转,且
,连接
并延长交
于点
.线段
与
有怎样的数量关系?问题探究:
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/9/4bf0ece1-c15a-4608-bb47-1d0f243a4d9e.png?resizew=221)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/9/3c771e6f-6e34-4abd-9f48-5b925465c7b8.png?resizew=189)
(1)先将问题特殊化.如图2,当点
在
上时,证明:
.
思路一:要证
,因为
,所以只要证
,若能证得
,问题就容易解决了.
思路二:要证
,因为
,又易得
,所以想到构造
,则有
,若能证得
,就可以得到
.
反思:这两种思路表面看起来完全不一样,其实这两种思路的思考问题的方式是一样的,就是由已知想可知,由未知想需知.还有,这两种证明思路用到的一些基础知识也是一样的,如:等角的余角相等,等边对等角,等角对等边,顶角相等的两个等腰三角形的底角也相等,等等.
(2)再探究一般情形.如图1,当点
不在
上时,证明(1)中的结论还成立.
问题拓展:
(3)如图2,过点
作
交
的延长线于点
.若
,
,直接写出四边形
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39c1b5e1f90cd17148f489e28ce1bc48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f0dd821851a38e5cbe13f63bee31fb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b96715995549e5e48494101570bb3bb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b96715995549e5e48494101570bb3bb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cd20cb6665aff8d05da3c7e31da204c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/9/4bf0ece1-c15a-4608-bb47-1d0f243a4d9e.png?resizew=221)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/9/3c771e6f-6e34-4abd-9f48-5b925465c7b8.png?resizew=189)
(1)先将问题特殊化.如图2,当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2e59617707e98c3441445392333b491.png)
思路一:要证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2e59617707e98c3441445392333b491.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb64353c99068a7a1a8508a22f5b25b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eea506dd038bbc99de25675fc42d14ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18ec350aa6fbe606d340112f53e1ffc4.png)
思路二:要证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2e59617707e98c3441445392333b491.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e08e67894f52d5e404c0531774017a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dda10216132192038ec152a9a089848c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d8302d0d250b1b9e4f92f5969bdf647.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/113a991940b5ef0385b25e3a16218e0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96197c5f26220141ae88e4c960062bd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2e59617707e98c3441445392333b491.png)
反思:这两种思路表面看起来完全不一样,其实这两种思路的思考问题的方式是一样的,就是由已知想可知,由未知想需知.还有,这两种证明思路用到的一些基础知识也是一样的,如:等角的余角相等,等边对等角,等角对等边,顶角相等的两个等腰三角形的底角也相等,等等.
(2)再探究一般情形.如图1,当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
问题拓展:
(3)如图2,过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f61fb14b549157473d2859f73d773fd3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1bd1adfe4cc6566218f19970c2fd3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6abf9450abb3961db463c1203fea58ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/657921f28d9ebc92f154ac16d3599b3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cf7e12dc03db7186feae41fd1751499.png)
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