学习了等腰三角形后,小明发现等腰三角形顶角顶点处的外角正好是其底角的两倍,于是他对作一个角等于已知角的两倍有了新的思路,请根据他的思路完成以下作图与推理证明填空,注明其中蕴含的数学依据:
用直尺和圆规,作线段
的垂直平分线
分别交
于点M,交
于点N,连接
.(只保留作图痕迹)
求证:
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/23/bf29c89a-5fab-4fa7-a082-646dca5b74f2.png?resizew=155)
证明:∵
是
的垂直平分线
∴
① ,(依据: ② );
∴
③ ,(依据:等边对等角).
∵
是
的外角
∴
(依据: ④ );
∴
.
用直尺和圆规,作线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abd13974aebe38eb2a1d744a01ea5aa5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/438f34bc8b04e8c494b91306ac6fe352.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c55ef3bdc97849bb74ccbb6e8e7df3d2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/23/bf29c89a-5fab-4fa7-a082-646dca5b74f2.png?resizew=155)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abd13974aebe38eb2a1d744a01ea5aa5.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b7dc2816d332f8761bfe2db1d9db87e.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a2979f64c85f82d8975d73ee1c342de.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b6500fbe1ea4a372d703502699b809e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c0da03ec477a5e17b7f4de370638024.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4b8dee1c3dde99a6f6334cc728f5bed.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c55ef3bdc97849bb74ccbb6e8e7df3d2.png)
更新时间:2024-01-23 07:31:32
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】在等边△ABC中,点D在BC边上,点E在AC的延长线上,DE=DA(如图1)
(1)求证:∠BAD=∠EDC;
(2)如图2,点E关于直线BC的对称点为M,连接DM,AM.
小明通过观察,实验提出猜想:在点D运动的过程中,始终有DA=AM,小明把这个猜想与同学们进行交流,通过讨论,形成了证明该猜想的两种想法:
想法1:要证明DA=AM,只需证△ADM是等边三角形;
想法2:连接CM,只需证明△ABD≌△ACM即可.
请你参考上面的想法,帮助小明证明DA=AM(选一种方法即可)
(1)求证:∠BAD=∠EDC;
(2)如图2,点E关于直线BC的对称点为M,连接DM,AM.
小明通过观察,实验提出猜想:在点D运动的过程中,始终有DA=AM,小明把这个猜想与同学们进行交流,通过讨论,形成了证明该猜想的两种想法:
想法1:要证明DA=AM,只需证△ADM是等边三角形;
想法2:连接CM,只需证明△ABD≌△ACM即可.
请你参考上面的想法,帮助小明证明DA=AM(选一种方法即可)
![](https://img.xkw.com/dksih/QBM/2020/7/24/2512850744713216/2513596780093440/STEM/b81d90ea-d0ed-438f-9ad8-1ed7bf77e550.png)
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名校
【推荐2】如图,直线
交x轴于B,交y轴于A,点C在
延长线上,过C作
于D,连
,设C点坐标为
,若![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b677ac5c69f16a1efc87147d94507a7d.png)
![](https://img.xkw.com/dksih/QBM/2020/12/6/2608460952936448/2609754685923328/STEM/4a02c3f78e3448df9b20884d331664ab.png?resizew=252)
(1)求证:
平分
;
(2)点E在
上,连
交
于F,
;求证:
.
![](https://img.xkw.com/dksih/QBM/2020/12/6/2608460952936448/2609754685923328/STEM/b9c4c3fc0b3f49e8890dc20d9482771d.png?resizew=261)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6d664af09d25fe943ed5634b9c04e7f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5a122e25cf4eb9f03ffe5ec823bfc31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba7204f43679af6935e494c59d40c6ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b677ac5c69f16a1efc87147d94507a7d.png)
![](https://img.xkw.com/dksih/QBM/2020/12/6/2608460952936448/2609754685923328/STEM/4a02c3f78e3448df9b20884d331664ab.png?resizew=252)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5a122e25cf4eb9f03ffe5ec823bfc31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42e7b8a59f8d66176463f3d71f882a26.png)
(2)点E在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1bd1adfe4cc6566218f19970c2fd3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5a122e25cf4eb9f03ffe5ec823bfc31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0b0308b7b53b16bd47e953e9d7eb1c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b51502d3e8d44b262c8c1721f60c0db.png)
![](https://img.xkw.com/dksih/QBM/2020/12/6/2608460952936448/2609754685923328/STEM/b9c4c3fc0b3f49e8890dc20d9482771d.png?resizew=261)
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解答题-问答题
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【推荐1】如图,在
中,
平分
,
的垂直平分线交
于点E,交
于点D,
,
,求∠C的度数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f80f699558ff62a31152df321b064f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dfb49d6ab0413a86cd4f3171967fd05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c15e2a36a31c62df44bf05d32e18ed6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/22/a407bec4-9110-43cc-aa86-18531449d437.png?resizew=181)
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解答题-作图题
|
适中
(0.65)
【推荐2】如图,已知在
中,
.
(1)请用尺规在
边上找一点
,使得
.(保留作图痕迹,不写作法)
(2)在(1)所作的图中,若
,则
______.
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(1)请用尺规在
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
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(2)在(1)所作的图中,若
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解答题-作图题
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适中
(0.65)
【推荐1】如图,已知
,请你仅用尺规,按下列要求作图和计算(保留作图痕迹,不写画法):
![](https://img.xkw.com/dksih/QBM/2020/12/8/2609804503916544/2609858845564928/STEM/1f9520c0c06143a98a717b139d4ca2f5.png?resizew=170)
(1)选取适当的边长,在所给的
图形上画一个含
的直角三角形
,并标上字母,其中点C为直角顶点,点B为另一锐角顶点;
(2)以
为一边作等边
;
(3)若设
,
边长为a,则
的长为__________.
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![](https://img.xkw.com/dksih/QBM/2020/12/8/2609804503916544/2609858845564928/STEM/1f9520c0c06143a98a717b139d4ca2f5.png?resizew=170)
(1)选取适当的边长,在所给的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
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(2)以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
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解答题-作图题
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适中
(0.65)
【推荐2】如图,已知线段
,
,用直尺和圆规按下列要求分别作一个等腰三角形
(保留作图痕迹,写出必要的文字说明).
的底边长为
,底边上的中线为
;
(2)
的底边长为
,腰上的中线为
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(2)
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