将矩形
绕点
顺时针旋转
,得到矩形
.
在
上,
与
交于点
,求证:
是等腰三角形;
(2)如图,连接
,当点
在
上时,求证:
;
(3)当
时,求旋转角
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e2515188f4678e21f2313f825912b7f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8d0e8404f347a0eb4c76f4d25d9bdac.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/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67d822262ff00915910e5b87d81ad1ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c2cc16f9b6b8988606829e2d20ed5b4.png)
(2)如图,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.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/9dda26560447cafbd6439ba5d8ad39b5.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79e31f427abcc8f71553f29e8008e4d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
更新时间:2024-05-12 18:06:51
|
相似题推荐
解答题-证明题
|
较难
(0.4)
【推荐1】(1)如图1,在△ABC中,∠ACB=2∠B,∠C=90°,AD为∠BAC的平分线交BC于D,求证:AB=AC+CD.(提示:在AB上截取AE=AC,连接DE)
![](https://img.xkw.com/dksih/QBM/2018/2/22/1887754903568384/1894226055643136/STEM/8cf7d16c790b403891a244021a1caaa9.png?resizew=171)
![](https://img.xkw.com/dksih/QBM/2018/2/22/1887754903568384/1894226055643136/STEM/c624a07697704e89ac66d5d4f2915e4a.png?resizew=151)
![](https://img.xkw.com/dksih/QBM/2018/2/22/1887754903568384/1894226055643136/STEM/27a97e8c5942415fa067deb218b1bcf1.png?resizew=207)
(2)如图2,当∠C≠90°时,其他条件不变,线段AB、AC、CD又有怎样的数量关系,直接写出结果,不需要证明.
(3)如图3,当∠ACB≠90°,∠ACB=2∠B ,AD为△ABC的外角∠CAF的平分线,交BC的延长线于点D,则线段 AB、AC、CD又有怎样的数量关系?写出你的猜想,并加以证明.
![](https://img.xkw.com/dksih/QBM/2018/2/22/1887754903568384/1894226055643136/STEM/8cf7d16c790b403891a244021a1caaa9.png?resizew=171)
![](https://img.xkw.com/dksih/QBM/2018/2/22/1887754903568384/1894226055643136/STEM/c624a07697704e89ac66d5d4f2915e4a.png?resizew=151)
![](https://img.xkw.com/dksih/QBM/2018/2/22/1887754903568384/1894226055643136/STEM/27a97e8c5942415fa067deb218b1bcf1.png?resizew=207)
(2)如图2,当∠C≠90°时,其他条件不变,线段AB、AC、CD又有怎样的数量关系,直接写出结果,不需要证明.
(3)如图3,当∠ACB≠90°,∠ACB=2∠B ,AD为△ABC的外角∠CAF的平分线,交BC的延长线于点D,则线段 AB、AC、CD又有怎样的数量关系?写出你的猜想,并加以证明.
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【推荐2】如图①,在正方形
中,
的顶点
,
分别在
,
边上,高
与正方形的边长相等,
![](https://img.xkw.com/dksih/QBM/2021/5/13/2720145023279104/2793302739091456/STEM/52bb6703-f1a3-495e-a25e-d3c24e39cbcd.png)
![](https://img.xkw.com/dksih/QBM/2021/5/13/2720145023279104/2793302739091456/STEM/ff368a25-a99c-4c05-9cec-c8ea981a8c11.png)
(1)求
的度数;
(2)在图①中,连接
分别交
、
于点
、
,将
绕点
顺时针旋转
至
位置,连接
,得到图②.求证:
;
(3)在图②中,若
,
,则
的值为_______.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f201a40fedca4ad14db193f4db2127e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://img.xkw.com/dksih/QBM/2021/5/13/2720145023279104/2793302739091456/STEM/52bb6703-f1a3-495e-a25e-d3c24e39cbcd.png)
![](https://img.xkw.com/dksih/QBM/2021/5/13/2720145023279104/2793302739091456/STEM/ff368a25-a99c-4c05-9cec-c8ea981a8c11.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e31edc5b71c488ca9942d70d9298f01.png)
(2)在图①中,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be8fc0d8b4548dca825ad1c98a64e455.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67edfaeb9a925d78b103e2f40a17e1e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83042953e7f15e984b2da2ee9ca678d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ed306582ae083118705d8f017df4906.png)
(3)在图②中,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e47710f547143221417662ba8891daa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de77d666a7f3ae69d593e412009180af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
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解答题-证明题
|
较难
(0.4)
名校
【推荐1】已知在
中,
,
,点
为线段
上一点,连接
.
![](https://img.xkw.com/dksih/QBM/2022/9/17/3068179518603264/3116411216183296/STEM/a68c83ccf2624a3b9f02e74a2d3b7fbd.png?resizew=387)
(1)如图 1 所示,在
右侧作等腰
,其中
,
.当
,
时,求
的长;
(2)如图 2 所示,在
右侧作等边
,连接
,点
为
中点,连接
交
点
.猜想线段
与
之间存在的数量关系, 并证明你的猜想;
(3)如图 3, 点
为
中点,将
沿
翻折得到
,连接
,点
为
的中点,连接
.当
的值最小时,连接
、
,直接写出
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fffa3d9c32da53b0ea0c338012ea20c.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/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/2022/9/17/3068179518603264/3116411216183296/STEM/a68c83ccf2624a3b9f02e74a2d3b7fbd.png?resizew=387)
(1)如图 1 所示,在
![](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/e2d212c1709b8e72a055cf1b5381ef64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a1b8d111d101afbbf301a2c56c6d15e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72f7d9f5e71bfef8188b1216c1276c2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dde9cb64ad52176fdef71b7446207b85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(2)如图 2 所示,在
![](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/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e72b2e1ff83e95df048745322982451.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0e57a13c665af88f326c9890072bf73.png)
(3)如图 3, 点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d42357598a706021b7328cd05f716c90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92a702d0c4373d1abe3b82985775a0af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92a702d0c4373d1abe3b82985775a0af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db54223bb3fc2fe2497213a4d1f94827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db54223bb3fc2fe2497213a4d1f94827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/020ebe1219437129358b986eb9e70bbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa9c7aa32fec81dd993bb4c5522e49db.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
名校
【推荐2】如图
,在平面直角坐标系中,等边
的边长为
,
在
轴上,点
在
轴上方,
边交
轴于点
,点
为
边上一点,连接
、
,已知
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/16/963d8684-d48f-4b39-8045-17c7daa4cd4e.png?resizew=384)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/16/79b8d713-f779-4e70-8a43-85425c5bdf44.png?resizew=215)
(1)求证:
;
(2)如图
,连接
,当
为直角三角形时,请直接写出点A的坐标;
(3)如图
,过点
作
,且
,当点
在
延长线上时,求点A的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f8c4c029e552954bd493b49aeab82d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80fe80cadc7049534072aea8c5c8fada.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaaf23a8678131fa115aece269792510.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/16/963d8684-d48f-4b39-8045-17c7daa4cd4e.png?resizew=384)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/16/79b8d713-f779-4e70-8a43-85425c5bdf44.png?resizew=215)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/421291381be28da4bd16560fd383b4a9.png)
(2)如图
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
(3)如图
![](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/35a19e004244a7fe4918d794a743b0aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a87efa1454c6082c9168c66b5a129f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐1】如图,直线
分别交
轴、
轴于
两点,点
为
的中点,点
在第二象限,且四边形
为矩形.
(1)求证:
互相平分;
(2)动点
从
出发,以每秒2个单位长度的速度,沿
向点
作匀速运动.设点
的运动时间为
秒.在动点
从
出发的同时,动点
从
出发,以每秒1个单位长度的速度,沿
向点
作匀速运动.当
中的一点到达终点后,该点停止运动,另一点继续运动,直至到达终点,整个运动停止.问:是否存在这样的
,使得直线
将四边形
的面积分成
两部分?若存在,请求出所有符合条件的
的值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52ca77881fc67388612bf10e4bdae60d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16e4e4c7a79d9d3cdb9ac5949d53e33e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8735e2de0ec29640d1eff9e043556030.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/21/0dd2ac24-8731-4dba-aa41-2c78fb43bbc4.jpg?resizew=654)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce1e553cbd73b107350ff9e12c8ae25b.png)
(2)动点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f00315ef58cec80e7a1681c37a86431b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db54223bb3fc2fe2497213a4d1f94827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
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【推荐2】如图,在矩形ABCD中,AE平分∠BAD交BC于点E,点F为AE上一点,连接BF,CF,满足BF=CF,AE=AD,延长BF交DE于点G,连接DF.
![](https://img.xkw.com/dksih/QBM/2022/8/8/3040044887203840/3066285427695616/STEM/128b90b9eb734840aae1d55b3c226177.png?resizew=142)
(1)求证:AB=AF.
(2)求证:EG=DG.
(3)若EG=2,求矩形ABCD的面积.
![](https://img.xkw.com/dksih/QBM/2022/8/8/3040044887203840/3066285427695616/STEM/128b90b9eb734840aae1d55b3c226177.png?resizew=142)
(1)求证:AB=AF.
(2)求证:EG=DG.
(3)若EG=2,求矩形ABCD的面积.
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【推荐1】转化是解决数学问题常用的思想方法之一,它可以在数与数、数与形、形与形之间灵活应用.请解答下面的问题:
如图1,在
中,
,
.
![](https://img.xkw.com/dksih/QBM/2022/4/26/2973503586689024/2977959069581312/STEM/fa25257a-ebb3-4715-b46f-3ee0a8616eda.png?resizew=598)
【基础巩固】
(1)将图1中
绕点B按顺时针方向旋转60°得到
(如图2),连结OC.求证:
.
【思考探究】
(2)将图1中
绕点B按顺时针方向旋转60°并缩小得到
(如图3),使
,连结OC,AD.
①求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3d42ffbafc4c3058abee609f50cdea7.png)
②用等式表示AD与AB之间的数量关系,并说明理由.
【拓展延伸】
(3)将图1中
绕点B按顺时针方向旋转某个角度(小于180°)并缩小得到
(如图4),使
,连结OC,AC,AD.当
时,求
的值.
如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/866b81a8384cce4f24867baca2e6820c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fca3734de79f7f50b552ef62b29dc7c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20ccc37b189fa2cbc269ca0b233dac37.png)
![](https://img.xkw.com/dksih/QBM/2022/4/26/2973503586689024/2977959069581312/STEM/fa25257a-ebb3-4715-b46f-3ee0a8616eda.png?resizew=598)
【基础巩固】
(1)将图1中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/866b81a8384cce4f24867baca2e6820c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41f0dadf037efedc90b39c57a6880a1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a7b5182b56259506c4418fdf1ef65.png)
【思考探究】
(2)将图1中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/866b81a8384cce4f24867baca2e6820c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41f0dadf037efedc90b39c57a6880a1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c466875b9b55e9b0488020bc951e42f.png)
①求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3d42ffbafc4c3058abee609f50cdea7.png)
②用等式表示AD与AB之间的数量关系,并说明理由.
【拓展延伸】
(3)将图1中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/866b81a8384cce4f24867baca2e6820c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41f0dadf037efedc90b39c57a6880a1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c466875b9b55e9b0488020bc951e42f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a7b5182b56259506c4418fdf1ef65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cf3d14eb32760482c383221784ee3f3.png)
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【推荐2】综合与实践
如图1,在矩形ABCD中,对角线AC与BD交于点O,将△OBC绕点C顺时针旋转,点B对应点为点E,点O对应点为点F.
![](https://img.xkw.com/dksih/QBM/2022/4/19/2961751391297536/2964382633459712/STEM/d94ed73660684cebb788219c77ca3b97.png?resizew=558)
(1)当点E落在CD的延长线上时,请解答以下两个问题
①如图1,若AB=2a,BC=2,连接OE,则
______(用含a的代数式表示);
②如图2,延长BD交EF于点G,试猜想BG与EF的位置关系并加以证明;
(2)如图3,在图1的基础上继续绕点C旋转△OBC,点B对应点为点E,点O对应点为点F,当点E落在BD的延长线上时,已知∠ACE=90°,求证:四边形CDEF是菱形.
如图1,在矩形ABCD中,对角线AC与BD交于点O,将△OBC绕点C顺时针旋转,点B对应点为点E,点O对应点为点F.
![](https://img.xkw.com/dksih/QBM/2022/4/19/2961751391297536/2964382633459712/STEM/d94ed73660684cebb788219c77ca3b97.png?resizew=558)
(1)当点E落在CD的延长线上时,请解答以下两个问题
①如图1,若AB=2a,BC=2,连接OE,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1e9ee6801c7fb25f88709c22b701912.png)
②如图2,延长BD交EF于点G,试猜想BG与EF的位置关系并加以证明;
(2)如图3,在图1的基础上继续绕点C旋转△OBC,点B对应点为点E,点O对应点为点F,当点E落在BD的延长线上时,已知∠ACE=90°,求证:四边形CDEF是菱形.
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