1 . 如图,在
中,
,在
的外部和内部(不在边上)分别取一点
,
,若
,
,
,
的补角等于
,
则下列结论:
①点
在线段
的垂直平分线上;②
;
③
;④
的最大值是14.
其中正确的结论是_________ .(填写所有正确结论的序号)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fffa3d9c32da53b0ea0c338012ea20c.png)
![](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/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffdfaf8ba10c7a0250437f4a317c5f44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d71e6ea7333dbc78d0a7b9bc3892f940.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0761165f1176f3a5fe4f7b052832316d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5157b42da58d55daad27d98b2fec15ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35803969509655f72b4118503ae1c966.png)
则下列结论:
①点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fdb6e71754d3e73fb4939ee00f24ab9c.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d27beebe45dba8f91743aab21f15b39b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
其中正确的结论是
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/24/b1e882c9-5def-44a5-aa68-d1d03275c01b.png?resizew=238)
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2 . 如图,
和
关于直线
对称,
和
关于直线
对称.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/24/8ad54631-6c59-4ef3-b5b4-f93b82942308.png?resizew=149)
(1)作出直线
(尺规作图,不写作法,保留作图痕迹);
(2)直线
与
相交于点O,且直线
,
所夹锐角
,求
的度数;
(3)在(2)的条件下,小颖得出
,请你运用所学知识判断小颖的结论是否正确,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8ee6e1d480ece7117e1f87ebf4bbeea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8ee6e1d480ece7117e1f87ebf4bbeea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25db870913249c9cd1c48e2bd2d2f6dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/24/8ad54631-6c59-4ef3-b5b4-f93b82942308.png?resizew=149)
(1)作出直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
(2)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97cf714ffb3fd5917a76b191640b55fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95b4189edb86626a657f2d8a57154308.png)
(3)在(2)的条件下,小颖得出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53f382cb01b9ead4df16d21c3bd5c200.png)
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3 . 阅读下列材料,完成相应任务.
【探究三角形中边与角之间的不等关系】
学习了等腰三角形,我们知道在一个三角形中,等边所对的角相等;反过来,等角所对的边也相等,那么,不相等的边所对的角之间的大小关系怎样呢?大边所对的角也大吗?下面是奋进小组的证明过程.
如图1,在△
中,已知
.求证
.
![](https://img.xkw.com/dksih/QBM/2022/10/15/3088002471641088/3089693671415808/STEM/d033c0b3b9554055851196a8ce9611f0.png?resizew=298)
证明:如图2,将△
折叠,使边
落在
上,点
落在
上的点
处,折痕
交
于点
.则
.
∵
________
(三角形外角的性质)
∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15b487f865bfb4750eee61bf9ec5059f.png)
∴
(等量代换)
类似地,应用这种方法可以证明“在一个三角形中,大角对大边,小角对小边”的问题.
(1)任务一:将上述证明空白部分补充完整;
(2)任务二:上述材料中不论是由边的不等关系,推出角的不等关系,还是由角的不等关系推出边的不等关系,都是转化为较大量的一部分与较小量相等的问题,再用三角形外角的性质或三边关系进而解决,这里主要体现的数学思想是________;(填正确选项的代码:单选)
A.转化思想 B.方程思想 C.数形结合思想
(3)任务三:根据上述材料得出的结论,判断下列说法,正确的有________(将正确的代码填在横线处:多选).
①在△
中,
,则
;
②在△
中,
,
,则△
是锐角三角形;
③
△
中,
,则最长边是
;
④在△
中,
,
,则
.
【探究三角形中边与角之间的不等关系】
学习了等腰三角形,我们知道在一个三角形中,等边所对的角相等;反过来,等角所对的边也相等,那么,不相等的边所对的角之间的大小关系怎样呢?大边所对的角也大吗?下面是奋进小组的证明过程.
如图1,在△
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d5bac918d34537ff02a518a63031aa9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaaae5a489951101a9c06fd94ff523d6.png)
![](https://img.xkw.com/dksih/QBM/2022/10/15/3088002471641088/3089693671415808/STEM/d033c0b3b9554055851196a8ce9611f0.png?resizew=298)
证明:如图2,将△
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce1132157a33c82610c2d5035493d024.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77936a859f39507de5a2d3070b13a60a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/289d7a880379d6060065c829b45b0ed6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3256a9f3b49b8e60ce44e8deec42d822.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b28daad9a051987ab64dc8a299d42bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66cb5797ef6c0853368ca92df9e5402b.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15b487f865bfb4750eee61bf9ec5059f.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaaae5a489951101a9c06fd94ff523d6.png)
类似地,应用这种方法可以证明“在一个三角形中,大角对大边,小角对小边”的问题.
(1)任务一:将上述证明空白部分补充完整;
(2)任务二:上述材料中不论是由边的不等关系,推出角的不等关系,还是由角的不等关系推出边的不等关系,都是转化为较大量的一部分与较小量相等的问题,再用三角形外角的性质或三边关系进而解决,这里主要体现的数学思想是________;(填正确选项的代码:单选)
A.转化思想 B.方程思想 C.数形结合思想
(3)任务三:根据上述材料得出的结论,判断下列说法,正确的有________(将正确的代码填在横线处:多选).
①在△
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df19eae422a11ecd874c01ce3d68178e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1494d156b2751301baf97ca7746cc971.png)
②在△
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a69d51f1998b6335cc7323b37537c251.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d36d0c89e9b5abbe28a7dad2468ad2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7eccdc904f71a7a6a02134f47e08072.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9429e394d7cf08f2cdbc7f1be7dfaaec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
④在△
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aca429d9688fa2721280ae7d7a00b37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98a691a85ae5a0bc49d3c411926ee1cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63dee45a1084de33934b9abb6bed96ad.png)
您最近一年使用:0次
名校
4 . △ABC中,∠A=∠B+∠C,则对△ABC的形状判断正确的是( )
A.锐角三角形 | B.直角三角形 | C.钝角三角形 | D.等边三角形 |
您最近一年使用:0次
2017-12-02更新
|
386次组卷
|
7卷引用:湖南长沙青竹湖湘一外国语学校2018-2019学年八年级上学期第一次月考数学试题