名校
解题方法
1 . 小宇和小明一起进行数学游戏:已知
,将等腰直角三角板
摆放在平面内,使点A在
的内部,且两个底角顶点B,C分别放在边
上.
(1)如图1,小明摆放
,恰好使得
,又由于
是等腰直角三角形,
,从而直接 可以判断出点A在
的角平分线上.请回答:小明能够直接 作出判断的数学依据是______.
(2)如图2,小宇调整了
的位置,请判断
平分
是否仍然成立?若成立,请证明,若不成立,请举出反例.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a563c50a7f6d10fa46339d7107fc85e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27935c1ef4df2d52ac697678a3c8f39d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66644d217fa5b91bea2b3889cc8f8aa8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/4/af9c46c0-8da4-458f-a827-6333204cecfa.jpg?resizew=265)
(1)如图1,小明摆放
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e06b166e28ca02cc0e2b1382e61ceb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ad037d6d1bddf8930944fd93b5a551b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27935c1ef4df2d52ac697678a3c8f39d.png)
(2)如图2,小宇调整了
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27935c1ef4df2d52ac697678a3c8f39d.png)
您最近一年使用:0次
2023-11-02更新
|
302次组卷
|
3卷引用:北京市海淀区中国人民大学附属中学2023~2024学年八年级上学期期中数学试题
名校
2 . 如图,
,
是
内部的射线且
,过点
作
于点
,过点
作
于点
,在
上取点
,使得
,连接
.
设
,给出下面三个结论:
①
;
②
;
③
.
上述结论中,所有正确结论的序号是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8e9be6f7e831d2155f99a57b7dfafe6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ead7a7815cec2f7d110710e85929053f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/804c0e2a375b5f4ff1c420532968efc3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4e2c014b93b1c39167bd467e2409dce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67d822262ff00915910e5b87d81ad1ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cb27447c815a8a495ba5bf7040e265d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f77555548d1922f63bff79d69fe53643.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9484e17359ab68ac3e63d12e43e83137.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f5663b1663bd94d7f71b2640cd3934d.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e0c4bbe9c1d0f77ad67aea3f8827d33.png)
上述结论中,所有正确结论的序号是( )
A.①② | B.①③ | C.②③ | D.①②③ |
您最近一年使用:0次
2024-05-18更新
|
530次组卷
|
3卷引用:2024年北京市石景山区九年级中考一模数学试题
3 . 在
中,
,在
上截取
,连接
.在
的外部作
,且
交
的延长线于点E.
![](https://img.xkw.com/dksih/QBM/2023/1/3/3144900883816448/3164003712540672/STEM/0d6f2317a5e9491080b1e880bbee768d.png?resizew=404)
(1)作图与探究:
①小明画出图1并猜想
.同学小亮说“要让你这个结论成立,需要增加条件:
_______°.”
请写出小亮所说的条件;
②小明重新画出图2并猜想
.他证明的简要过程如下:
![](https://img.xkw.com/dksih/QBM/2023/1/3/3144900883816448/3164003712540672/STEM/5b191bd706b54f5eb05cbf683debd2c0.png?resizew=230)
请你判断小明的证明是否正确并说明理由;
(2)证明与拓展:
①借助小明画出的图2证明
;
②延长
到F,使
,连结
.补全图形,猜想
与
的数量关系并加以证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bc0d39e5b649a96b32334c8c46a1785.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4dd6e7c88601b4c50b06f1238fdd95d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4119cf3af35e995cc09a4a296a6230f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67d822262ff00915910e5b87d81ad1ba.png)
![](https://img.xkw.com/dksih/QBM/2023/1/3/3144900883816448/3164003712540672/STEM/0d6f2317a5e9491080b1e880bbee768d.png?resizew=404)
(1)作图与探究:
①小明画出图1并猜想
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/934a9508c176f44bf58f88715bd98f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4db07c6ce6c8b0e96a3470c6a3491334.png)
请写出小亮所说的条件;
②小明重新画出图2并猜想
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61e76ba9d6497948aca946e896ea40da.png)
![](https://img.xkw.com/dksih/QBM/2023/1/3/3144900883816448/3164003712540672/STEM/5b191bd706b54f5eb05cbf683debd2c0.png?resizew=230)
请你判断小明的证明是否正确并说明理由;
(2)证明与拓展:
①借助小明画出的图2证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba11242dcc61d3c7c3555b598b5fdc89.png)
②延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c4491b334748bceb87485a33b38638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07394b663b3ad02f040a5355f2d763eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/024015816ece1fd176186ed0f04db8f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ed24d7acba0b3a7ebf4d520296424a3.png)
您最近一年使用:0次