如图,在
中,点
在
上,
,
,将
沿
折叠至
,
交
于点
.
(1)求
的度数;
(2)求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.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/7f3844363acad4b97e3d4dc93a6ab74b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c15416b74b2ecbcfa38cf34a9ffff730.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9f8f01137e92c0f2e63467036ae9cce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ccbf98ff1b1f121ee3aa3dec108ba0c.png)
![](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)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc382c4f315de17f293d3d273626ade2.png)
![](https://img.xkw.com/dksih/QBM/2020/3/26/2434933350989824/2435013226446848/STEM/25ff94661a864cde95749b8e2019069a.png?resizew=181)
2020九年级·广东·专题练习 查看更多[2]
更新时间:2020-04-05 17:10:00
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相似题推荐
解答题-问答题
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【推荐1】如图1,∠ACD是△ABC的外角,∠ABC与∠ACD的角平分线交于点O.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/9/87988d2d-8138-4afa-afc8-b2618b123c73.png?resizew=352)
(1)若∠ABC=66°,∠ACB=34°,则∠A= °,∠O= °;
(2)探索∠A与∠O的数量关系,并说明理由;
(3)若AB
CO,AC⊥BO,求∠ACB的度数.
(4)如图2,将△ABC纸片沿DE折叠,使点A落在点
处,且
平分∠ABC,
平分∠ACB,若
=120°,则∠1+∠2的度数为 .
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/9/87988d2d-8138-4afa-afc8-b2618b123c73.png?resizew=352)
(1)若∠ABC=66°,∠ACB=34°,则∠A= °,∠O= °;
(2)探索∠A与∠O的数量关系,并说明理由;
(3)若AB
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
(4)如图2,将△ABC纸片沿DE折叠,使点A落在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e663220a66eff19da6a71e46b397db2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6eb97aff0960e2640314888a38e7169c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e399037a56758e6922524248946a416d.png)
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【推荐2】如图,在折纸活动中,小明制作了一张
纸片,点D,E分别在边AB,AC上,将
沿着DE折叠压平,A与A'重合.
![](https://img.xkw.com/dksih/QBM/2020/3/12/2417893370306560/2417954102722560/STEM/2fcbb0189bf4438e9f276db08851b03b.png?resizew=158)
(1)若
,则
___________;
(2)若
,则
___________;
(3)由(1)(2)探索
与
之间的数量关系,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://img.xkw.com/dksih/QBM/2020/3/12/2417893370306560/2417954102722560/STEM/2fcbb0189bf4438e9f276db08851b03b.png?resizew=158)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/feb1606f91a55ec822fa19b28c441b7d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa61f1be96d581867ea9f074420a2252.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01847a44e59cfd6c285af241c64f04cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa61f1be96d581867ea9f074420a2252.png)
(3)由(1)(2)探索
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca4678ff1b3ea3bd09ed3494a0efe31c.png)
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名校
【推荐1】数学是以数量关系和空间形式为主要研究对象的科学,数学实践活动有利于我们在图形运动变化的过程中去发现其中的位置关系和数量关系,让我们在学习与探索中发现数学的美,体会数学实践活动带给我们的乐趣,如图①,在矩形
中,点E、F、G分别为边
的中点,连接
,H为
的中点,连接
.将
绕点B旋转,线段
和
的位置和长度也随之变化,当
绕点B顺时针旋转
时,请解决下列问题:
(1)图②中,
,此时点E落在
的延长线上,点F落在线段
上,连接
,直接写出
与
之间的数量关系为:__________;
(2)图③中,当
,求
的值;
![](https://img.xkw.com/dksih/QBM/2023/10/8/3341833223094272/3342342700318720/STEM/a1d2ee70423848a3b42d36144f552821.png?resizew=4)
(3)当
时,
________;(直接写出结果即可)
(4)在(2)的条件下,连接图③中矩形的对角线
,并沿对角线
剪开,得
(如图④).点M、N分别在
上,连接
,将
沿
翻折,使点C的对应点P落在
的延长线上,若
平分
,
与
相交于点Q,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ff8c7dfea0fb5f9dc5bdac28756ec6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6e9aad3473c2843c9f11eb16ecd36fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a679040c4d556723e482bacbab41356d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cafbe2751f4f4c5a8e676818195e9111.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f2ea13010e2399194be2a681310543e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9cc387d47c842af4f4d9c9399934b67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6b41d4070854edfaa24071137b314cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f2ea13010e2399194be2a681310543e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7a0387fc1258f31e44a10068c0ccfd0.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/9/5a28cdc3-e8dc-4453-980d-73f861031d22.png?resizew=346)
(1)图②中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3570a95f68349fcd9417fcda62e78e7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79ff575e55857af133edb24c8e61504f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cafbe2751f4f4c5a8e676818195e9111.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6b41d4070854edfaa24071137b314cb.png)
(2)图③中,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1185a2f8f144fc04917afb94304d621c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29e15cfa1cd8e8159d9246897678d26d.png)
![](https://img.xkw.com/dksih/QBM/2023/10/8/3341833223094272/3342342700318720/STEM/a1d2ee70423848a3b42d36144f552821.png?resizew=4)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/104730c96dfc637c700b982bbd13d7e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24d3913865c22e150166d463fcbd97dc.png)
(4)在(2)的条件下,连接图③中矩形的对角线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34f457946f2909889491ba8545d6e5c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa29fe6cd9eb51c184f6299d437375cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12225a1a1eda07908309f8100cc34726.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa29fe6cd9eb51c184f6299d437375cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3d9792485ccd1ba479ceba6397c15ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e984138407bc056575914a6bc9907faa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3d9792485ccd1ba479ceba6397c15ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa29fe6cd9eb51c184f6299d437375cb.png)
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【推荐2】已知:如图,△DAC、△EBC均是等边三角形,点A、C、B在同一条直线上,且AE、BD分别与CD、CE交于点M、N.
![](https://img.xkw.com/dksih/QBM/2011/1/15/1577487378980864/1577487457222656/STEM/717079bbdc394c5fa3078f955e42de97.png)
求证:(1)AE=DB;
(2)△CMN为等边三角形.
![](https://img.xkw.com/dksih/QBM/2011/1/15/1577487378980864/1577487457222656/STEM/717079bbdc394c5fa3078f955e42de97.png)
求证:(1)AE=DB;
(2)△CMN为等边三角形.
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