如图,在△ABC中,∠BAC是钝角,按要求完成下列画图.(不写作法,保留作图痕迹)
(1)用尺规作∠BAC的平分线AE和AB边上的垂直平分线MN;
(2)用三角板作AC边上的高BD.
(1)用尺规作∠BAC的平分线AE和AB边上的垂直平分线MN;
(2)用三角板作AC边上的高BD.
![](https://img.xkw.com/dksih/QBM/2018/12/28/2106373741051904/2108047240331264/STEM/ca4ef1f46e6b432580e126ee133356b0.png?resizew=134)
18-19八年级上·全国·单元测试 查看更多[4]
沪科版2018-2019学年八年级上册期末模拟检测数学卷(已下线)2018年12月26日 《每日一题》人教版八上(期末复习)-轴对称(已下线)2019年12月23日 《每日一题》轴对称安徽省六安市裕安区2019-2020学年八年级上学期期末数学试题
更新时间:2018-12-05 15:09:07
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解答题-作图题
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适中
(0.65)
【推荐1】如图,在
中,按以下步骤作图:
![](https://img.xkw.com/dksih/QBM/2021/4/21/2704558464262144/2705101015916544/STEM/9d898407-5e35-44bd-9ae6-4de551549e70.png)
①以点
为圆心,任意长为半径作弧,分别交边
,
于点
,
;
②分别以点
,
为圆心,大于
的相同长度为半径作弧,两弧交于点
;
③作射线
交
于点
.
(1)根据上述步骤补全作图过程(要求:规作图,不写作法,保留作图痕迹);
(2)如果
,
,那么
的面积与
的面积的比值是________.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://img.xkw.com/dksih/QBM/2021/4/21/2704558464262144/2705101015916544/STEM/9d898407-5e35-44bd-9ae6-4de551549e70.png)
①以点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
②分别以点
![](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/65026a6b6402cb599e14be8023a3f6a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
③作射线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
(1)根据上述步骤补全作图过程(要求:规作图,不写作法,保留作图痕迹);
(2)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54275b7e571660d0a9e0370fbfe5050b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b939af5ba06e279cce39396aaf0fae06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bc727c642cbc2181476b7dd8eca471e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6d178d1a6ab4178996033cf1ca0c244.png)
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解答题-作图题
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适中
(0.65)
【推荐2】如图,直线L1、L2表示两条相交的公路,点A,B表示两个小镇,现在要在它们附近建一个加油站,使加油站到两条公路的距离相等,并到两个小镇的距离也相等,加油站应建在何处?请你在图上标出加油站的位置.(用尺规作图,并保留作图痕迹)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/5/07031f28-416a-481d-bf64-230fba8a0214.png?resizew=190)
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解答题-问答题
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适中
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【推荐1】如图,已知
及线段
.求作点
,使得
,点
到
,
的距离相等.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d7b2fe01a33c4825f9974ed9663a99c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ed66431681da1db8f7cb0f40cd19201.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/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://img.xkw.com/dksih/QBM/2022/12/8/3126552464334848/3128474702979072/STEM/26cac96ddba9496da0d7a6a579a4bf5c.png?resizew=188)
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解答题-作图题
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适中
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【推荐2】下面是小青设计的“过直线外一点作这条直线的平行线”的尺规作图过程.
已知:直线l及直线l外一点P.
求作:直线
,使得
.
作法:如图,
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/380ab6b1-e6a9-44d5-9e61-dd8334bd6ff2.png?resizew=394)
①在直线l上取点A,连接
;
②作线段
的垂直平分线
,分别交直线l,直线
于点B,O;
③以点O为圆心,
长为半径画弧,交直线
于另一点Q;
④作直线
.所以直线
就是所求作的直线.
根据小青设计的尺规作图过程,
(1)使用直尺和圆规,补全图形;(保留作图痕迹)
(2)完成下面的证明.
证明:连接
,
∵线段
的垂直平分线交
于点O,
∴
,(_____________________)(填推理的依据)
又∵
,
______,
∴
,(_____________________)(填推理的依据)
∴
,
∴
.
已知:直线l及直线l外一点P.
求作:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b43460283aa3418a0ed8296ad9ac7eb1.png)
作法:如图,
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/380ab6b1-e6a9-44d5-9e61-dd8334bd6ff2.png?resizew=394)
①在直线l上取点A,连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
②作线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
③以点O为圆心,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
④作直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
根据小青设计的尺规作图过程,
(1)使用直尺和圆规,补全图形;(保留作图痕迹)
(2)完成下面的证明.
证明:连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
∵线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3b9f123cfacbfe6e5504111fbfd174c.png)
又∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26f98ff3666810eb183b66a86f747e84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a836d2dfc31d2bfc949bac8403cf2a4e.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ee17bf358df97490bc56b1e5a15a678.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba43ac19e5698d6368a28cb92e1da845.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b43460283aa3418a0ed8296ad9ac7eb1.png)
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