取一副三角尺按图①所示的方式放在一起,
,
,固定三角尺
,将三角尺
以点A为中心按顺时针方向旋转一个大小为
的角
得到
,如图②所示.当
为多少度时,能使得
?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ab5c45a72849d2cae1d65b282b5bd19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f81e24376a13d648c2ed0dc73bc710e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d78fc7fcb2762de28dcef8aa3aa0e49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc8a9f02b655ae21040875a3111aeb3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c430808cb91d66ce60b1e2f83f129db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c30f6595dd643813b11ad71df61a10dc.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/28/12fcd76d-a5d4-4eed-9a8a-aca3544c146a.png?resizew=301)
更新时间:2023-10-22 19:23:48
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【推荐1】如图,已知AC
FE,∠1+∠2=180°,AC平分∠FAD,EF⊥BE于点E,∠FAD=80°,求∠BCD的度数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/12/e549c86f-2ca5-465a-aa60-45dffb55e3a3.png?resizew=158)
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【推荐2】如图,直线
,
,
两两相交,交点分别为点
,
,
,
,点
在线段
上,过点
作
交
于点
,过点
作
交
于点
.求
的度数.
请将下面的解答过程补充完整,并填空(数学式或理由)
解:
,
,( )
,
,( )
.(等量代换)
,
.
![](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://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.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/5400056ce5e7d2c6ea8714392e36237b.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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c436f108fd4921dae15ecff19270237e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c197d8b99f2eb7477947e53461b5d548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e17ff7f305c47e1b2d1b510293edb770.png)
请将下面的解答过程补充完整,并填空(数学式或理由)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/22/6ecf2f4c-db99-417e-9ef5-70c73dad2f89.png?resizew=148)
解:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93bfa26ae659a9e6f9b4a45df98a37ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a29c5917341d7c2e3c522d531e9228df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2086b50836dd9ce76a653a854e5b4ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad9b06bf2eec6784143746ad604682ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d2a0fd12401f3e6e2b90f67f12cc6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a514cde9df83ab68307392332aa7ad46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8afc0b85f3e9abb7199710a79cdcfd1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83873a9d782f2588c5eedbfe73f9bc2f.png)
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【推荐1】综合与实践
旋转是初中学习的一种全等变换,通过旋转可以将已知条件中“分散”的条件相对地“集中”在一起,构成新的联系,从而解决问题.同时,旋转时图形中出现“有公共端点的线段相等”的条件,所以在等腰(或等边)三角形、正方形中常进行旋转变换.
(1)正方形中的“旋转":如图①,点E、点F分别是正方形的边DC、BC上的点,连接AF、FE、AE,若
,则BF、DE、EF之间的数量关系为______.
![](https://img.xkw.com/dksih/QBM/2022/5/24/2986464594894848/2990523190730752/STEM/7e15a079-0f5f-4654-9384-ca71973c68cc.png?resizew=182)
问题解决:将
绕点A顺时针旋转90°,得到
,则点G、点B、点F三点______,可证明
______,从而得出结论.请你完成上述全等关系的证明.
(2)如图②,P为正方形ABCD内一点,且
,
,
,请你确定
的度数:
=______.
![](https://img.xkw.com/dksih/QBM/2022/5/24/2986464594894848/2990523190730752/STEM/d352c5a2-8c68-41d6-aa6d-faf4c66a9a31.png?resizew=189)
小杰同学的思路是:设法将PA、PB、PC相对集中,于是将
绕点B顺时针旋转90°得到
,连接PE,确定
与
的形状分别为:______,问题得以解决.
(3)等边三角形中的“旋转”:请你参考小杰同学的思路,解决下面问题:
如图③,P点是等边三角形ABC内一点,若
,
,请你直接写出:以线段PA、PB、PC的长度为边长的三角形的各内角的度数分别为______.
旋转是初中学习的一种全等变换,通过旋转可以将已知条件中“分散”的条件相对地“集中”在一起,构成新的联系,从而解决问题.同时,旋转时图形中出现“有公共端点的线段相等”的条件,所以在等腰(或等边)三角形、正方形中常进行旋转变换.
(1)正方形中的“旋转":如图①,点E、点F分别是正方形的边DC、BC上的点,连接AF、FE、AE,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/192155e6a3aade305b76b1eb7c75e30c.png)
![](https://img.xkw.com/dksih/QBM/2022/5/24/2986464594894848/2990523190730752/STEM/7e15a079-0f5f-4654-9384-ca71973c68cc.png?resizew=182)
问题解决:将
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bc727c642cbc2181476b7dd8eca471e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98f4b8626204840314e7168d676a66e7.png)
(2)如图②,P为正方形ABCD内一点,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcc532cfe64300cb3da9e04a307c957a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8825d400f453c5c17a7beeb1cc9a9cf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be41b05e11ba5eadaaed9a224b949774.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb686e4f5e3938575bc547e849d5513f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb686e4f5e3938575bc547e849d5513f.png)
![](https://img.xkw.com/dksih/QBM/2022/5/24/2986464594894848/2990523190730752/STEM/d352c5a2-8c68-41d6-aa6d-faf4c66a9a31.png?resizew=189)
小杰同学的思路是:设法将PA、PB、PC相对集中,于是将
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/357265c532428e886a643e8e653eec9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad09a769a75b107390b9eeccc929f761.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b6accdd9b317c922d335e44911df357.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/729684f958ad60b8e905fe1e1da53c03.png)
(3)等边三角形中的“旋转”:请你参考小杰同学的思路,解决下面问题:
如图③,P点是等边三角形ABC内一点,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c285633d641b9402a8f1046d0bcd2325.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39c7b0e15bfcf4bd7214320bc40f5373.png)
![](https://img.xkw.com/dksih/QBM/2022/5/24/2986464594894848/2990523190730752/STEM/221fae70-b9da-467b-b771-7ca2a40ce41e.png?resizew=158)
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【推荐2】如图,在
中,
,
,
,将
绕点B旋转
,点A落在点
处,求
的长度.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3018c687427b6257767eda4a8c6612.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e3262fc038bbec5e7c8cc47df08bef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7aeb2a8d1437eeb4482c3b6ad9f315.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfe639eab78eafd2d40ea70aa5d3f21d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6024fd4532f5f981deac4582c799a6ef.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/8/837f2521-090f-46e9-8877-b14c7b2af4b5.png?resizew=174)
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