1 . 张老师善于通过合适的主题整合教学内容,帮助同学们用整体的、联系的、发展的眼光看问题,形成科学的思维习惯.下面是张老师在“利用角的对称性构造全等模型”主题下设计的问题,请你解答.
(1)【观察发现】
①如图1,
是
的角平分线,
,在
上截取
,连接
,则线段
与
的数量关系是 ;
的角平分线
相交于点P,当
时,线段
与
的数量关系是 ;
如图3,在四边形
中,
,
的平分线与
的平分线恰好交于
边上的点P,试判断
与
的数量关系,并说明理由.
在(2)的条件下,若
,
,当
有一个内角是
时,请直接写出边
的长.
(1)【观察发现】
①如图1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcc2f5f6d9efe3852a2329ea927abcf7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da8bc2b99ffb78e8b6ca21fccdbe2906.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45de0916d8d18f2eb495e08e6bbc3016.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/998329f9cdb86f5d60d7d5d70fc3781e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fb26d84907c923278ac4626a9d58947.png)
如图3,在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/609ada36dd56b33279103ebc1f90bbac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4189a0821a0ffab9dc171ecd279ba442.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39b8d91afc34e4a9b0fdbb6bafb9087.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
在(2)的条件下,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc34db5860990e51ba31edc8cdd077c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afcd54ff42ebdc70cb273cd5909d549f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c025ee3317be1099b7bf03a11e37ed4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79a97bb4dcfab4ec7539bc783d563c49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
您最近一年使用:0次
2024·河南郑州·三模
2 .
中,
,过点
作
,点
为边
上一个动点,将射线
绕点
逆时针旋转
,交射线
于点
,连接
.
问题初现:
(1)如图1,若
,则线段
与
的数量关系为______;
类比探究:
(2)如图2,若
,求出线段
与
的数量关系,并说明理由;
拓展应用:
(3)在(2)的条件下,若
,
,点
在
上运动,当四边形
为轴对称图形时,请直接写出线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b455b110a30c1533d0a0657e0e48ac33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
问题初现:
(1)如图1,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05d35d8d8bb0dc17f2f86fe5b230a2b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb6ede9761b5b90f8dc137708e1ee90f.png)
类比探究:
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fd465973943bcd766b5275ee204bbf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb6ede9761b5b90f8dc137708e1ee90f.png)
拓展应用:
(3)在(2)的条件下,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d70dc2c20619a4fc12a0cfda59af5b69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65a3e478bb87d094e3a0af30dd10ae8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/168315930b269417340f8464e9eec451.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
您最近一年使用:0次
3 . 综合与实践
【问题情境】
数学实践课上,同学们以“角的旋转”为主题开展活动探究.小智同学首先制作了一个正方形纸片
,然后将等腰直角三角板
的锐角顶点和正方形的顶点
重合,当三角板
绕着正方形的顶点
顺时针旋转
时,直线
分别交射线
于点
,探究线段
和
的数量关系:
【特例猜想】
(1)如图1,小智发现,当三角板旋转到点
和点
重合时,线段
和
的数量关系为______.
【数学思考】
(2)小智认为根据特殊情形可以归纳出一般结论:线段
和
的数量关系恒成立.小智的结论是否正确?若正确,请你仅就图2的情形进行证明;若不正确,请说明理由.
【拓展探究】
(3)在
旋转过程中,当正方形
的边长为
,
的面积也为6时,请直接写出
的面积.
【问题情境】
数学实践课上,同学们以“角的旋转”为主题开展活动探究.小智同学首先制作了一个正方形纸片
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbfe67affcf628c91c031340c43d7be0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a26260c10afb34f543d86b67898134f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd4914267aa0598458ee61b520fc4617.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f50b3ae183997b707d16eb4e7f6712fa.png)
【特例猜想】
(1)如图1,小智发现,当三角板旋转到点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f50b3ae183997b707d16eb4e7f6712fa.png)
【数学思考】
(2)小智认为根据特殊情形可以归纳出一般结论:线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f50b3ae183997b707d16eb4e7f6712fa.png)
【拓展探究】
(3)在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f8c4c029e552954bd493b49aeab82d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a5e0a51c9e14fb246b0ba0b231c1e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9eda61683bb1d4d62441f0625097b477.png)
您最近一年使用:0次
2024-03-12更新
|
82次组卷
|
2卷引用:2024年河南省南阳市桐柏县二模数学试题
4 . 综合与实践
在四边形
中,将
边绕点
顺时针旋转
至
(
),
的角平分线所在直线与直线
相交于点
,
与
边或
边交于点
.
【特例感知】
(1)如图1,若四边形
是正方形,旋转角
,则
_____.
【类比迁移】
(2)如图2,若四边形
是正方形且
,试探究在旋转的过程中
的值是否为定值?若是,请求出该定值;若不是,请说明理由;
【拓展应用】
(3)如图3,若四边形
是菱形,
,
,在旋转的过程中,当线段
与线段
存在
倍的关系时,请直接写出
的长.
在四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fbe78a4267ce3e10466a1ef3058f2bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/060705794ef87cc71dac40c57f27b1d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
【特例感知】
(1)如图1,若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d506cde7e074adc6d8be3c2b11e47482.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e80371754b2bb6259920dd580ba24f37.png)
【类比迁移】
(2)如图2,若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb0d13654f181ab352d6b453e5a6c692.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13a2e6494cf8d2dff0746a9bb72cef43.png)
【拓展应用】
(3)如图3,若四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db54223bb3fc2fe2497213a4d1f94827.png)
您最近一年使用:0次
5 . 《九章算术》勾股章一五问“勾股容方”描述了关于图形之间关系的问题∶知道一个直角三角形较短直角边(“勾”)与较长直角边(“股”)的长度,那么,以该三角形的直角顶点为一个顶点、另外三个顶点分别在该三角形三边上的正方形的边长就可以求得.(我们不妨称这个正方形为该直角三角形的“勾容正方形”)
其文如下:
题:今有勾五步,股十二步,问勾中容方几何?
答:方三步,十七分步之九.
术:并勾、股为法,勾股相乘为实,实如法而一,得方一步.
“题”、“答”、“术”的意思大致如下∶
问题:一个直角三角形的两直角边的长分别为5和12,它的“勾容正方形”的边长是多少?
答案:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1da6aeb767ea82b782addd1a74ce518a.png)
解法:
(1)问题探究
根据“勾股容方”中描述的直角三角形与其“勾容正方形”之间的关系,请提出一个数学命题,并证明;
(2)类比探究
“勾股容圆”:一个直角三角形的两直角边的长分别为5和12,它的内切圆的半径是多少?
(3)拓展运用
某市去年举办中小学校园文化展览,举办方在某广场搭建了一个展馆(平面示意图为正方形),并综合考虑参展主题、参展单位等因素将展馆划分为四个展区,规划方案如图所示,其中,
是
的中点,点
,
在
边上,
垂直平分
,垂足为
,
.
今年,为了让更多人参与,举办方拟在北湖公园的一块菱形场地上搭建展馆,该菱形场地面积为
,且两条对角线长度之和为
,考虑到展览安全、公园环境等各方面的因素,若举办方希望沿用去年展馆及展区的规划方案,则展馆的建设需满足以下要求:①展馆平面示意图中的A,B,C,D四个点分别落在菱形场地的四条边上;②展馆主入口
的宽度为
,去年的规划方案是否可行?请说明理由.
其文如下:
题:今有勾五步,股十二步,问勾中容方几何?
答:方三步,十七分步之九.
术:并勾、股为法,勾股相乘为实,实如法而一,得方一步.
“题”、“答”、“术”的意思大致如下∶
问题:一个直角三角形的两直角边的长分别为5和12,它的“勾容正方形”的边长是多少?
答案:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1da6aeb767ea82b782addd1a74ce518a.png)
解法:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d55e5ab49750c88c2cc1adbe3784c5ca.png)
(1)问题探究
根据“勾股容方”中描述的直角三角形与其“勾容正方形”之间的关系,请提出一个数学命题,并证明;
(2)类比探究
“勾股容圆”:一个直角三角形的两直角边的长分别为5和12,它的内切圆的半径是多少?
(3)拓展运用
某市去年举办中小学校园文化展览,举办方在某广场搭建了一个展馆(平面示意图为正方形),并综合考虑参展主题、参展单位等因素将展馆划分为四个展区,规划方案如图所示,其中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53b95463a97c60db3250cb641bf6523d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9954fb448161566ce61787f143ff0cd4.png)
今年,为了让更多人参与,举办方拟在北湖公园的一块菱形场地上搭建展馆,该菱形场地面积为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb81e2e2edd68c29eaca8841717566d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f05ba29eb90358e2211e1f7ba6423fa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdae78f4d3b8d8213ac3ac9a9567eb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e978c77cb0d7eff794447241e9829867.png)
您最近一年使用:0次
6 . 如图1,在
中,
,
,
,点
,
分别是边
,
的中点,连接
将
绕点
逆时针方向旋转,记旋转角为
.
时
______;
②当
时,
______.
(2)拓展探究:试判断当
时,
的大小有无变化?以下是就图2的情形给出的证明过程,请你补全:
∵
,
③ .
又∵旋转
,
∴
,
.
(3)用以上结论解决问题:当
绕点
逆时针旋转至
,
,
三点在同一条直线上时,请在备用图中画出图形,并写出求线段
的长 .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60d9142db4dd2ef151bf3d4a63afb61e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.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/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f32c425e7a8ed6d0d79c6e8e2df4302.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d631f45bc652539853f236952afa5bbf.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/8e7e8c4e8015bc1a44a89460e1dc0d63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ce24b781c66474602b5ba6627241531.png)
②当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddd284be60584dfae454b1a125468947.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ce24b781c66474602b5ba6627241531.png)
(2)拓展探究:试判断当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/783d872617eed2bbd474035156b6caaf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/625000a942ec1b76a1176284be6d6520.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e090774467026264e014d721dc524a92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d4194d4552abf5e4b4c2146f8ee4d3f.png)
又∵旋转
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b93ced49680a8fcc69eb8c7cce729d0.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90d6dc07c483555ff56b78919314ab42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aeb71b9be18458e4501b1edeacc1a53.png)
(3)用以上结论解决问题:当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d631f45bc652539853f236952afa5bbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3182db896bc2462331796e2a6108363.png)
您最近一年使用:0次
7 . 【问题提出】
如图1,在
中,
,
,
为
内一点,连接
,将
绕点
顺时针旋转
得到
,连接
并延长到点
,使
,连接
,
,
.求证:
,
.
“神州小组”的解题思路:将线段
借助平行线进行平移,如图2,过点
作
平行
交
的延长线于点
,这样可以将证明
和
的关系转化为
和
的关系;
“智慧小组”的解题思路:结合
为
的中点构造三角形的中位线,如图3,过点
作
平行
交
延长线于点
,从而借助三角形中位线性质,将
和
的关系转化为
和
的关系.
(1)请你选择其中一个小组的思路,或者用你自己探究的思路写出证明过程;
【思维训练】
王老师为了进一步让学生体会平行线在图形证明中的作用,又出示了下列问题:
(2)如图4,在
中,
,
,
为
上一点,将
绕点
逆时针旋转
得到
,连接
,
,
为
中点,连接
并延长交
的延长线于点
,若
,探究
,
,
之间的数量关系,并说明理由;
【能力提升】
(3)“北斗小组”的同学在【问题提出】的基础上对该问题又进一步拓展:连接
,若
为平面内一点,
,
,
,其他条件不变,求
的长.
如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f586a2079d0e382ef843f4dbe068566e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8e41916523511064a97de39b0f2b323.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0fa1aa5a7a5bb172ed4603f17c8b2c6.png)
“神州小组”的解题思路:将线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06e322e0c87479bba874db9ae9ba36b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
“智慧小组”的解题思路:结合
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdae78f4d3b8d8213ac3ac9a9567eb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21037e170bdbb322558e79c40c00b454.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(1)请你选择其中一个小组的思路,或者用你自己探究的思路写出证明过程;
【思维训练】
王老师为了进一步让学生体会平行线在图形证明中的作用,又出示了下列问题:
(2)如图4,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3018c687427b6257767eda4a8c6612.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/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf1438142deeac876fc7dc50552e552.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e222294cdeab74d9a75a941565248a72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cad4595d5352b2884568a59d8d766a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
【能力提升】
(3)“北斗小组”的同学在【问题提出】的基础上对该问题又进一步拓展:连接
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c2868676ab7a19ca70e8ccf3dd00a0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/833cfda415649b832cc136caed392753.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d70dc2c20619a4fc12a0cfda59af5b69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
您最近一年使用:0次
8 . 某兴趣小组开展综合实践探究活动:
已知
为等边三角形,点
,
分别在边
,
上,且
,
,
相交于点
,连接
.探究过程如下:
(1)①如图1,当点
为
中点时,
;
②如图2,当
时,
;
(小智积极思考,提供如下解题思路:
延长
至点
,使得
,连接
,
.
,
,
,
.
.
又
,
.
又
,
是等边三角形.……)
【类比探究】
(2)如图3,当
时,求
的值;
【拓展延伸】
(3)①当
时,直接写出
的值(用含
的式子表示);
②当点
在
延长线上,点
在
延长线上时,且
,直线
,
相交于点
,连接
,请直接写出
的值(用含
的式子表示).
已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d42218a68301d770accaaefb96b19f8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
(1)①如图1,当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1de94901207fc22febd4bf4760fd970.png)
②如图2,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc9b0d3cf342e065b4c8e21443bfbfbc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8228b61810f3d48ab3bb118d0e6a07c6.png)
(小智积极思考,提供如下解题思路:
延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/587eab9a26310dc294effac917a4178a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4fb9bc6163bd3f8aa1a8b0a70c9cbf8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fbf18a89d2bc8795a4393d02b0f970e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d42218a68301d770accaaefb96b19f8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93fe27a2f7a406c1dbbe4d95db109744.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33414fdfa12f64e52fd438690063b1f0.png)
又
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed62aa0840db9c22386593d596593de4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6711c81a608af5754aa603b820753002.png)
又
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93cc50ad2ba6b7f2571f6d83a689c969.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9dd2f4363d0d5996571b458d2539bde2.png)
【类比探究】
(2)如图3,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942a9a6bde4a5b9803b68b1e9065de62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/424dd73a238dad799c9296e9ff829253.png)
【拓展延伸】
(3)①当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3ca85a8426af15089c9a0e599b0748a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/424dd73a238dad799c9296e9ff829253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
②当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7aed9117f66f0f21602ccd31cce376ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcce0893aa84f73e5f5d05ddab5d0848.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
您最近一年使用:0次
9 . 【探究发现】
(
)如图
,在正方形
中,
是
边上一点(不与端点重合),
为
延长线上一点,且
,连接
,点
在线段
上,且
,连接
.
求证:
;
【类比迁移】
(
)如图
,在矩形
中,
是
边上一点(不与端点重合),
为
延长线上一点,且
,连接
,点
在线段
上,且
,连接
.求证:
;
【拓展提高】
(
)如图
,在菱形
中,
是
边上一点(不与端点重合),
为
延长线上一点,且
,连接
,点
在线段
上,且
,连接
.若
,求
的长.
(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1bd1adfe4cc6566218f19970c2fd3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f2e37b8f3fbfa523962606580d8fbad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6de220dff974128c6da83f975d263695.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/244d77a322628c8d26d3d296905d703b.png)
【类比迁移】
(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1bd1adfe4cc6566218f19970c2fd3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f2e37b8f3fbfa523962606580d8fbad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6de220dff974128c6da83f975d263695.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0110d258447eb72a8ae01ba9ef8fd3be.png)
【拓展提高】
(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1bd1adfe4cc6566218f19970c2fd3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f2e37b8f3fbfa523962606580d8fbad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6de220dff974128c6da83f975d263695.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56a53685e119d7a30df92da3b2c91156.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
您最近一年使用:0次
10 . 某数学兴趣小组在数学实践课上开展了“菱形折叠”研究活动.
第一步:每人制作边长都为7的菱形纸片若干个,四个顶点为A、B、C、D(为保持一致,活动中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bca5f6366db8d915043332f818b65d7c.png)
小组内制作图形各点名称命名规则相同);
第二步∶在边
上分别取点M、N(不含端点),将四边形
沿
翻折,使线段
的对应线段
经过顶点 D(点A、B分别与点 E、F对应).
操作判断![](https://staticzujuan.xkw.com/quesimg/Upload/formula/098a96d1e67d5e74d6122c8dfa63f183.png)
则
______.
迁移探究
(2)缜密小组按上述步骤折叠后如图2所示,已知![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8861f0a5a206281022132864219f34d.png)
求
的长;
拓展延伸
(3)创新小组按上述步骤折叠后,要使
是以
为直角边的直角三角形,请你在图3 中帮他们画出满足条件的图形(草图即可),并求出对应的
的长.
第一步:每人制作边长都为7的菱形纸片若干个,四个顶点为A、B、C、D(为保持一致,活动中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bca5f6366db8d915043332f818b65d7c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c915b4ce31fabfd4703c547291ad9277.png)
第二步∶在边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ba48366317ebea1c9dd5e4e67e03092.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baa76cfd79a2ff6b28f370e54f4eb51d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
操作判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/098a96d1e67d5e74d6122c8dfa63f183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c915b4ce31fabfd4703c547291ad9277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf86f352a109022b6a849690bd0def8b.png)
迁移探究
(2)缜密小组按上述步骤折叠后如图2所示,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8861f0a5a206281022132864219f34d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c915b4ce31fabfd4703c547291ad9277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
拓展延伸
(3)创新小组按上述步骤折叠后,要使
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f44ca79d5e12bd02c393ba7f0b31c8c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b46c607b3deac746c0ef3389ad8f65c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7785afeeaf274892253d04b4f693b367.png)
您最近一年使用:0次