如图,已知
与
互为补角,且
,
![](https://img.xkw.com/dksih/QBM/2020/2/4/2391863009116160/2392043430920192/STEM/f20a110dadbb4818a277833a31353935.png?resizew=166)
(1)求证:
;
(2)若
,
平分
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5b69d40b75d582c4b8ffa2369af1d41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d57899ad4774aed9ccc7bd23db72153.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1598ad60d36f87f7fed1a58cf5c2c42.png)
![](https://img.xkw.com/dksih/QBM/2020/2/4/2391863009116160/2392043430920192/STEM/f20a110dadbb4818a277833a31353935.png?resizew=166)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39b12aa9d4f934868c3e4f51f73e7c89.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb1150e7caf86393601b45976f94f3e5.png)
19-20八年级上·山东聊城·期末 查看更多[4]
山东省聊城市临清市2019-2020学年八年级上学期期末数学试题山东省聊城市东阿县2019-2020学年八年级上学期期末数学试题(已下线)2020-2021学年八年级数学上册《单元测试定心卷》(人教版)第十三章 轴对称(能力提升)(已下线)【单元测试】第十三章 轴对称(夯实基础过关卷)-【冲刺高分】2021-2022学年八年级数学上册培优拔高必刷卷(人教版)
更新时间:2020-02-05 00:07:43
|
相似题推荐
解答题-证明题
|
较难
(0.4)
名校
解题方法
【推荐1】在数学活动课上,数学老师出示了如下题目:
如图①,在四边形
中,
是边
的中点,
是
的平分线,
.
求证:
.
小聪同学发现以下两种方法:
方法1:如图②,延长
、
交于点
.
方法2:如图③,在
上取一点
,使
,连接
、
.
(1)请你任选一种方法写出这道题的完整的证明过程;
(2)如图④,在四边形
中,
是
的平分线,
是边
的中点,
,
,求证:
.
如图①,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.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/2947ca8e0cdbeb4aab80ce9e7b63ba98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0facf189b2a3153beb7b9e077d3b1146.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/609ada36dd56b33279103ebc1f90bbac.png)
小聪同学发现以下两种方法:
方法1:如图②,延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
方法2:如图③,在
![](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/90c3e1ce324fc3e667d8a563a0b3bfff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
(1)请你任选一种方法写出这道题的完整的证明过程;
(2)如图④,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2947ca8e0cdbeb4aab80ce9e7b63ba98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e393b5e9ee7efa40a9aa6af8604c4e9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a291c43cfa0df7a643be250c0a5e233f.png)
![](https://img.xkw.com/dksih/QBM/2020/4/5/2435073324916736/2435638228475904/STEM/f494c93115464ef8bca8aef056b3e459.png?resizew=550)
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解答题-问答题
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名校
解题方法
【推荐2】如图1所示,已知点
在直线
上,点
,
在直线
上,且
,
平分
.
![](https://img.xkw.com/dksih/QBM/2021/9/9/2804338510962688/2804874375749632/STEM/2cb39cdb-64f0-4928-8d87-9beb4b7b1ddd.png)
(1)判断直线
与直线
是否平行,并说明理由.
(2)如图2所示,
是
上点
右侧一动点,
的平分线
交
的延长线于点
,设
,
.
①若
,
,求
的度数.
②判断:点
在运动过程中,
和
的数量关系是否发生变化?若不变,求出
和
的数量关系;若变化,请说明理由.
![](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/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/599cec6e67881a10de3e9b882b7260d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/482e68d608de7675e15bb759acd8204c.png)
![](https://img.xkw.com/dksih/QBM/2021/9/9/2804338510962688/2804874375749632/STEM/2cb39cdb-64f0-4928-8d87-9beb4b7b1ddd.png)
(1)判断直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(2)如图2所示,
![](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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90429ba8b029e318a971acda776aaa1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27e66b12019cdf68327d34c90dff7c04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7c57b07f75e97d9f84718bd495ebcf4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab62b021f18fb25fd887bf2e97f50f79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1210737f4cab007dccc7090350d547a6.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1316fd11f19387d23376021949b3953f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d5ac9f51fa7814c126dd273c7e54a6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/595522dfc96cc92f1d84ea0f298bb738.png)
②判断:点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
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【推荐1】(1)已知:如图1,
,易知
______.
![](https://img.xkw.com/dksih/QBM/2020/10/31/2583128517001216/2585243653578752/STEM/c1d2d96a-7a4b-4f7a-9c33-68815885fed5.png?resizew=196)
(2)如图2,
,
,
是直线
上的两点,猜想,
,
,
,
这四个角之间的关系,写出以下三种情况中这四个角之间的关系,并选择其中之一进行说明.
![](https://img.xkw.com/dksih/QBM/2020/10/31/2583128517001216/2585243653578752/STEM/7e280c2a-1d90-43e3-9eb2-7104748052cd.png?resizew=514)
①图中四个角的关系:______
②图中四个角的关系:______
③图中四个角的关系:______
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45a0a5049cfbc5292060fdc736f6fe1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e1e8d3e9fe016f1581fc5d16c36d12b.png)
![](https://img.xkw.com/dksih/QBM/2020/10/31/2583128517001216/2585243653578752/STEM/c1d2d96a-7a4b-4f7a-9c33-68815885fed5.png?resizew=196)
(2)如图2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45a0a5049cfbc5292060fdc736f6fe1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b9cb8e6ff801523b0304576cd69fd2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/285182faee06028ddf7aa9960f0c1106.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eaf65a624434a093e63797bb768772fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
![](https://img.xkw.com/dksih/QBM/2020/10/31/2583128517001216/2585243653578752/STEM/7e280c2a-1d90-43e3-9eb2-7104748052cd.png?resizew=514)
①图中四个角的关系:______
②图中四个角的关系:______
③图中四个角的关系:______
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【推荐2】【问题初探】
(1)在张老师的课堂上,正引导学生证明“三角形内角和定理”,如图1,已知:
.求证:
,结合之前拼摆的实践操作经验,学生们多用于下列两种证明思路:
①如图2,延长
到
,过点
作射线
,相当于把
,
都移到了顶点
的位置,利用图形特点获得
,
,
的数量关系;
②如图3,过点
作直线
,相当于把
,
都移到了顶点
的位䈯,再利用图形特点获得
,
,
的数量关系;
请你选择上述的一种证明思路,并写出证明过程.
【类比分析】
(2)在回顾解题思路时,张老师带领同学们重点总结了转化思想,两种解题思路都利用了“平行线”的等角转化的功能;为了帮助学生更好地感悟转化思想,将图3进行了变换并提出了下面问题,请你解答.
如图4,已知
,过点
作直线
,
为线段
上一点,连接
,
,若
,
,
,求
的度数.
【学以致用】
(3)如图5,
,
,
,若
,
,
,请你判断
,
,
三者之间的数量关系,并证明你的结论.
(1)在张老师的课堂上,正引导学生证明“三角形内角和定理”,如图1,已知:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/791e819abbe4ecc6f2e7209839c4fc0b.png)
①如图2,延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aea70178f34595abab1a383326c74d3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
②如图3,过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e7b5caf93535240f8e073fd0a2bcff2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
请你选择上述的一种证明思路,并写出证明过程.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/11/b89d6500-24fa-4bed-8aba-292fc3554fbe.png?resizew=379)
【类比分析】
(2)在回顾解题思路时,张老师带领同学们重点总结了转化思想,两种解题思路都利用了“平行线”的等角转化的功能;为了帮助学生更好地感悟转化思想,将图3进行了变换并提出了下面问题,请你解答.
如图4,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e7b5caf93535240f8e073fd0a2bcff2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aa0df7f1e45f9de29e802c7f19a4f64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe1a6ce0b35896c8a1c687a4376e71f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66eec809b500cb5dda09be178bdf4ef0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71f184b7ca3a71739408e078670aa22d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/093b40702557d7291c5dea9dccccea2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f7deac829e20432ffdce1919b3e13e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c478d6dea51f33674c9ec39a00e783b.png)
【学以致用】
(3)如图5,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73ee3aefffa15b9148f07c9c1dc73250.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c91d7433312ae63780eb67d4079071e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3841a37cf57bf05520b69c0cbbb8141b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcc45fc94fbe621bc2aa8afa56b9731e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/406a2d99e3ca070902c5695f9d4f32c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1318b44ce8675d6c2b7708a5b3c5a5de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f435efcc7869eec21bdba1ed81dc3f5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/11/2390a3bb-1c75-4585-8e9f-de02ee1a887a.png?resizew=272)
您最近一年使用:0次
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【推荐3】如图1,在△ABC中,延长BC到D,使CD=AB,点E是BD下方一点,连接AE,DE,CE,且∠B=∠ACE=∠CDE.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/28/2d86838c-ccb1-4dab-9e91-785443413afd.png?resizew=466)
(1)如图1,若∠D=30°,则∠CAE=______度;
(2)如图2,若∠ACB=90°,AF=8cm,将DE沿直线CD翻折得到DF,连接CF,连接AF交CE于G,当
时,求AG的长度;
(3)如图3,若AC=BC,将DE沿直线CD翻折得到DF,连接CF,连接AF交CE于G,交CD于H,若DF=m,AB=n,(
),请直接 写出线段CH的长度(用含m,n的代数式表示).
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/28/2d86838c-ccb1-4dab-9e91-785443413afd.png?resizew=466)
(1)如图1,若∠D=30°,则∠CAE=______度;
(2)如图2,若∠ACB=90°,AF=8cm,将DE沿直线CD翻折得到DF,连接CF,连接AF交CE于G,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07e04e60854cbd5584b2ed0e4f305d92.png)
(3)如图3,若AC=BC,将DE沿直线CD翻折得到DF,连接CF,连接AF交CE于G,交CD于H,若DF=m,AB=n,(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f537c893dfe2661ba4273cf218c72d34.png)
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解答题-证明题
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名校
【推荐1】如图1,已知锐角△ABC中,CD、BE分别是AB、AC边上的高,M、N分别是线段BC、DE的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/28/53d376eb-8bff-49a0-b9fe-85c6b0830843.png?resizew=321)
(1)求证:MN⊥DE.
(2)连结DM,ME,猜想∠A与∠DME之间的关系,并证明猜想.
(3)当∠A变为钝角时,如图2,上述(1)(2)中的结论是否都成立,若结论成立,直接回答,不需证明;若结论不成立,说明理由.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/28/53d376eb-8bff-49a0-b9fe-85c6b0830843.png?resizew=321)
(1)求证:MN⊥DE.
(2)连结DM,ME,猜想∠A与∠DME之间的关系,并证明猜想.
(3)当∠A变为钝角时,如图2,上述(1)(2)中的结论是否都成立,若结论成立,直接回答,不需证明;若结论不成立,说明理由.
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【推荐2】【思维启迪】
(1)在证明“三角形内角和定理”时,小明只撕下三角形纸片的一个角拼成图1即可证明,其中与
相等的角是 ;
![](https://img.xkw.com/dksih/QBM/2022/12/30/3142197653716992/3161259816484864/STEM/40cdc625f03d45508c9a0094caab6a65.png?resizew=393)
【类比迁移】
(2)如图2,在四边形
中,
和
互余,小明发现四边形
中这对互余的角可类比(1)中的思想进行拼合:先作
,再过点C作
于点E,连接
,发现
,
,
之间的数量关系是 ;
(3)如图3,在四边形
中,连接
,
,点O是
两边垂直平分线的交点,连接
,
.
①求证:
;
②连接BD,如图4,已知
,
,
,求
的长.(用含
,
的式子表示)
(1)在证明“三角形内角和定理”时,小明只撕下三角形纸片的一个角拼成图1即可证明,其中与
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://img.xkw.com/dksih/QBM/2022/12/30/3142197653716992/3161259816484864/STEM/40cdc625f03d45508c9a0094caab6a65.png?resizew=393)
【类比迁移】
(2)如图2,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3981e7286d41960daf4e110c1c84e03a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17c9e1ef4bb574a8dba55c84a213a633.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/783b84ed8d927b77491092f7d2ee2989.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/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
(3)如图3,在四边形
![](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/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27e2c20d959ff812b6349efce365a996.png)
①求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22fe309928b35b06e206780a53a9c297.png)
②连接BD,如图4,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3be96420ac78c8621fcb47a45514fa8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34293b0e5b0ccd82aaf2197561865efc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17f98c69f957606da0462987564f3a79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://img.xkw.com/dksih/QBM/2022/12/30/3142197653716992/3161259816484864/STEM/7782dd0d6cff4cdf8e52af665b37887b.png?resizew=480)
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解答题-计算题
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较难
(0.4)
【推荐1】如图1,在△ABC 中,∠ACB=90°,∠B=20°,点O在AB边上.连结OC,已知OA=OB=OC.
![](https://img.xkw.com/dksih/QBM/2020/7/27/2514752541949952/2514945516576768/STEM/72f50c9e54214769bd553c8d2be06f94.png?resizew=106)
(1)直接写出∠A的度数;
(2)如图2,将 OA 绕着点 O 逆时针旋转角至 OP,连结BP、CP.
①当=40°时,请你通过计算说明∠BCP=∠BPC;
②当∠PBC=∠PCB时,求旋转角的度数(0°<β<180°).
![](https://img.xkw.com/dksih/QBM/2020/7/27/2514752541949952/2514945516576768/STEM/730706bdee0548a598dd9c5a33126579.png?resizew=116)
![](https://img.xkw.com/dksih/QBM/2020/7/27/2514752541949952/2514945516576768/STEM/a28dc1dcc93d49a4a53e908aae738aae.png?resizew=161)
![](https://img.xkw.com/dksih/QBM/2020/7/27/2514752541949952/2514945516576768/STEM/72f50c9e54214769bd553c8d2be06f94.png?resizew=106)
(1)直接写出∠A的度数;
(2)如图2,将 OA 绕着点 O 逆时针旋转角至 OP,连结BP、CP.
①当=40°时,请你通过计算说明∠BCP=∠BPC;
②当∠PBC=∠PCB时,求旋转角的度数(0°<β<180°).
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解答题-证明题
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解题方法
【推荐2】已知:在边长为
的正方形
中,点
为对角线
上一点,且
.将三角板的直角顶点与点
重合,一条直角边与直线
交于点
,另一条直角边与射线
交于点
(点
不与点
重合),将三角板绕点
旋转.
(1)如图,当点
、
在线段
、
上时,求证:
;
时,求
的面积;
(3)当
为等腰三角形时,求线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb93acd927b9dc02b62ea38e7e1d5732.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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
(1)如图,当点
![](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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b30155e0e3cf7c5146d3311e5b8da93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbec162724a013514df1738bb55e1732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5fa7dd60b071d132afbfdaf170c1020.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5fa7dd60b071d132afbfdaf170c1020.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
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