1 . 如图,在菱形
中,
,
,点
为对角线
上一动点(不与点
重合),且
,连接
交
延长线于点
.
①
:
②当
为直角三角时,
;
③当
为等腰三角形时,
或者
;
④连接
,当
时,
平分
.
以上结论正确的是________ .(填正确的序号)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68b40d0d2f3cdd8981bb792ad87efb42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.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/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cbbc26a6f4e97047943f9acf03a26e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67d822262ff00915910e5b87d81ad1ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/197afe2823d441bd68ed89a9d393fb29.png)
②当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60634341a9603e24b2bbc6960abe3d31.png)
③当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39c11bca40fcddfc1afbd7c742ca0000.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/587547b09e85c4779ae0e341bce4c968.png)
④连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a702c324e0c76150540c3d32df802077.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36719f1e764ee0e719b65c49fae84677.png)
以上结论正确的是
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/13/d7f13b16-0ef8-4fae-904d-d85cce5ebb75.png?resizew=172)
您最近一年使用:0次
2 . 如图,将
绕点
顺时针旋转
得到
,边
,
相交于点
,连接
.下列结论:①
;②
平分
;③
;④
.其中所有正确结论的序号是______ .
![](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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21037e170bdbb322558e79c40c00b454.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce74654b7088989396bb03fb619b0428.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfd94dd51562ecbee6edd4265326b765.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5588b9238d940f09fd25191b930ce936.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/817ccf96200350828be4a7a503a5ad02.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/28/3e787b10-14f4-45be-b889-77c046a064f7.png?resizew=229)
您最近一年使用:0次
2022-12-09更新
|
132次组卷
|
4卷引用: 福建省福州市长乐区2022-2023学年九年级上学期期中数学试卷
福建省福州市长乐区2022-2023学年九年级上学期期中数学试卷福建省福州市第十五中学2023-2024学年九年级上学期月考数学试题(已下线)专题23.13 旋转(全章分层练习)(提升练)-2023-2024学年九年级数学上册基础知识专项突破讲与练(人教版)(已下线)专题3.6 图形的旋转(分层练习)(基础练)-2023-2024学年八年级数学下册基础知识专项突破讲与练(北师大版)
名校
3 . 如图,点D是等边
边
上的一个动点,以
为边作等边
,连接
.则下列结论正确的是______ (填正确的序号).
①
;②D在
上运动的过程中线段
有最小值;③四边形
的面积是定值;④
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.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/4eedae8d316c76e3d0b451256de03fb9.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dc59641467014c8be833e0781f04b1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bc1cbcd6d00f0c36bad8254297d9f33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8196909b00ad21a6ac480fcbf1be1fb9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/6/ecee2adf-950a-46f8-8931-e0e20ac2ac8b.png?resizew=175)
您最近一年使用:0次
4 . 如图,点
是等边三角形
内部一点,连接
、
、
,且
,现将
绕点
顺时针旋转到
的位置,对于下列结论:①
是等边三角形;②
;③
;④
.其中结论正确的是__________ (填序号).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c3fe3eddc09024fdbce00cd08ab4b98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9524e3810e06dc781285f1289e75d653.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5f517953a21c2a45fd8465072c44bfc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3da7bcea5a45eeae211f5851f12a7517.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90de825299eb86f8661b70a8accfa596.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02413d06ae10743c4ae0748ef02a2131.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f4cb33cdb3e2994ac7b9a0abbabed2.png)
![](https://img.xkw.com/dksih/QBM/2022/1/8/2897166123499520/2916338960744448/STEM/4d2810f6ec5f4bc8bb9777e32017da20.png?resizew=177)
您最近一年使用:0次
5 . 数学概念:如图①,在△ABC中,D为∠ABC的对边AC上一点(点D不与点A、C重合),连接BD.若∠ADB和∠CDB这两个角中至少存在1个与∠ABC相等,则称BD为△ABC中∠ABC的等角分割线.
![](https://img.xkw.com/dksih/QBM/2021/10/29/2839691527626752/2914084275544064/STEM/e658bece-a4a4-44ae-be2f-fcb31a9e1f89.png?resizew=268)
(1)概念理解:如图②,在Rt△ABC中,∠C=90°,∠B=60°.分别画出∠B和∠C的等角分割线BD、CE.(画图工具不限,并做出适当的标注)
(2)知识运用:在△ABC中,∠A=50°,∠ACB=70°.已知∠ABC、∠ACB的等角分割线BD、CE相交于点O,求∠BOC的度数.
(3)深入思考:下列关于“等角分割线”的结论:
①钝角三角形中的钝角有2条等角分割线;
②三个角都不相等的三角形中,最小的角没有等角分割线;
③三角形的高、角平分线可能是该三角形中的等角分割线;
④任意一个三角形中最少有1条等角分割线,最多有3条等角分割线.
其中所有正确结论的序号是 .
![](https://img.xkw.com/dksih/QBM/2021/10/29/2839691527626752/2914084275544064/STEM/e658bece-a4a4-44ae-be2f-fcb31a9e1f89.png?resizew=268)
(1)概念理解:如图②,在Rt△ABC中,∠C=90°,∠B=60°.分别画出∠B和∠C的等角分割线BD、CE.(画图工具不限,并做出适当的标注)
(2)知识运用:在△ABC中,∠A=50°,∠ACB=70°.已知∠ABC、∠ACB的等角分割线BD、CE相交于点O,求∠BOC的度数.
(3)深入思考:下列关于“等角分割线”的结论:
①钝角三角形中的钝角有2条等角分割线;
②三个角都不相等的三角形中,最小的角没有等角分割线;
③三角形的高、角平分线可能是该三角形中的等角分割线;
④任意一个三角形中最少有1条等角分割线,最多有3条等角分割线.
其中所有正确结论的序号是 .
您最近一年使用:0次
6 . 如图,点
在
内部,点
与点
关于
对称,点
与点
关于
对称.甲、乙两位同学各给出了自己的说法:甲:若
,则
是等边三角形;乙:若
,则
.对于两位同学的说法,下列判定正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d7b2fe01a33c4825f9974ed9663a99c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b9cb8e6ff801523b0304576cd69fd2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6131160eaee962470abc7771df265c6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc51601b6c84e2ffade0e91c9feaa970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8c84a56823287fa2b878302cff66fcd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0aefee236ce95b71927b9048409c5c68.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/6/f0e4b685-d0e5-4b79-a272-8a50359cdb32.jpg?resizew=146)
A.甲正确 | B.乙正确 | C.甲、乙都正确 | D.甲、乙都错误 |
您最近一年使用:0次
7 . 在七年级的学习中,我们知道:(1)三角形的内角和等于
;(2)等腰三角形的两个底角相等.下面我们对这两点知识作进一步思考和探索.
(一)三角形的外角.
三角形内角的一条边与另一条边的反向延长线组成的角,称为三角形的外角.如图1,
就是
的
的外角.在三角形的每个顶点位置都可以找到它的外角,以
为例,我们探索外角与其它角的关系.
(①__________),
(②___________)
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a5a716592d862464b3ff814e45d0e11.png)
(③__________)
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/635b1af26e27be60f4cf4817e6d4e1d9.png)
由此我们得到了三角形外角的两条性质:
(1)三角形的一个外角等于和它不相邻的两个内角的和.
(2)三角形的一个外角大于任何一个和它不相邻内角.
问题1:
(1)请在以上括号①②③中填上适当的理由;
(2)请在图1中分别画出
和
的一个外角,并分别标注为
,
.
(二)等腰三角形的两个底角相等.
等腰三角形的两个底角相等,我们简述为“等边对等角”,数学小组据此提出问题:三角形中大边对的内角也大,即“大边对大角”正确吗?小聪同学进行了如下探索.
问题2:
如图2,
中
,求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b24a07ee331866778ea413e465a4f0ce.png)
证明:如图3,在
边上截取
,连接![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f7f05dfb173e003ab30d2a424b96637.png)
(④__________)
(整体大于部分)
又
(⑤_________)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/314df17ec77fb1e71d07c1c9cd9574d0.png)
由此说明三角形中大边对大角.
请在以上括号④⑤中填上适当的理由.
问题3:
如图4,
中
,
,请判断
是否成立,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54e7a123c9cc0e058db28841fb0edcf3.png)
(一)三角形的外角.
三角形内角的一条边与另一条边的反向延长线组成的角,称为三角形的外角.如图1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5b69d40b75d582c4b8ffa2369af1d41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5b69d40b75d582c4b8ffa2369af1d41.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/4/6ea8918a-30b6-42e6-8480-e3af911e746c.png?resizew=204)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4280c3963b4900adb983db9a3a4b58ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59a1b09bae4841be75f196673a627497.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ffc2f065a5d5febb87359016eac379d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a5a716592d862464b3ff814e45d0e11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4d0f3991ab2d191e46e36e3072388b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0d17adae48fae0dea0ab332763dc91e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/635b1af26e27be60f4cf4817e6d4e1d9.png)
由此我们得到了三角形外角的两条性质:
(1)三角形的一个外角等于和它不相邻的两个内角的和.
(2)三角形的一个外角大于任何一个和它不相邻内角.
问题1:
(1)请在以上括号①②③中填上适当的理由;
(2)请在图1中分别画出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d57899ad4774aed9ccc7bd23db72153.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/605f2976297a0deaa1602ef09d6a5afa.png)
(二)等腰三角形的两个底角相等.
等腰三角形的两个底角相等,我们简述为“等边对等角”,数学小组据此提出问题:三角形中大边对的内角也大,即“大边对大角”正确吗?小聪同学进行了如下探索.
问题2:
如图2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abcb980da8e86b4cfd322616dc84fc6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b24a07ee331866778ea413e465a4f0ce.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/4/dec32640-3e28-4f44-b8f0-5bafff271626.png?resizew=127)
证明:如图3,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fc13fe21e64d9b45614ed43be847904.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/4/aaa65144-a2b8-4e26-b3e4-7420e387dd04.png?resizew=128)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f7f05dfb173e003ab30d2a424b96637.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d98228bd5ecb89ef69c62a71f8e1ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6818402824ac026a750a8bcc4c2db372.png)
又
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddd37e385a92dc12298ae8278cf58386.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/314df17ec77fb1e71d07c1c9cd9574d0.png)
由此说明三角形中大边对大角.
请在以上括号④⑤中填上适当的理由.
问题3:
如图4,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e53497af8899cb299d762f1a4f46a55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90c251ed1472ba56f13a80abbfeb06c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c9af7ab732d431dd78e84db9586d3cc.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/4/f79f2beb-bbf5-4925-b9e3-721596dd078b.png?resizew=128)
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8 . 对于问题:过直线外一点作这条直线的垂线,小明和小亮给出两种不同的作法:
作法I:
(1)在直线
上任取一点
,连接
.
(2)以
为圆心,线段
的长度为半径作弧,交直线
于点
.
(3)分别以
,
为圆心,线段
的长度为半径作弧,两弧相交于点
.
(4)作直线
.直线
即为所求(如图1).
作法Ⅱ:如图2.
(1)以
为圆心,任意长为半径画弧,交直线
于
,
两点;
(2)连接
,作
的垂直平分线交
于点
;
(3)以
为圆心,
的长为半径画弧,交直线
于点
;
(4)作直线
,则直线
即为直线l的垂线
对于以上两个方案,判断正确的是( )
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/29/0dd6074d-e247-43ac-8742-37966cb4e4c8.png?resizew=184)
作法I:
(1)在直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(2)以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
(3)分别以
![](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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(4)作直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/29/71105851-b8c4-405c-9833-99bed97977d2.png?resizew=161)
作法Ⅱ:如图2.
(1)以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
(3)以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
(4)作直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f50b3ae183997b707d16eb4e7f6712fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f50b3ae183997b707d16eb4e7f6712fa.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/29/e7620042-1f44-40e8-b698-982fca1695eb.png?resizew=272)
对于以上两个方案,判断正确的是( )
A.方案I正确 | B.方案Ⅱ正确 | C.方案I、Ⅱ均正确 | D.方案I、Ⅱ均不正确 |
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9 . 数学老师在课上呈现一个几何图形,如图,∠1=∠2,AB⊥CD于点E,过点E作一条直线分别交线段BC,AD于点F,G.同学们根据图形进行大胆猜想.小方说:当∠3=∠1=50°时,可求得∠CFE的度数.小何说:当BF=CF时,可证得EG⊥AD.
(1)依据小方说的条件,你求得∠CFE= .(直接写出答案)
(2)依据小何说的条件,请你判断他的结论是否正确,并说明理由.
(1)依据小方说的条件,你求得∠CFE= .(直接写出答案)
(2)依据小何说的条件,请你判断他的结论是否正确,并说明理由.
![](https://img.xkw.com/dksih/QBM/2021/12/19/2875636560732160/2877182165983232/STEM/9efd61387bfd458a9159b3800c0a92a3.png?resizew=197)
您最近一年使用:0次