1 . 综合与实践
问题情境
在综合与实践课上,老师组织同学们以“正方形纸片的折叠”为主题开展数学活动.请你解决活动过程中产生的下列问题.如图1,现有正方形纸片
,先对折得到对角线
,接着折叠使点
落到
上的点
处,再展开,得到折痕
,连接
.
观察计算
(1)在图1中,
的值是________________;
操作探究
(2)如图2,在图1的基础上,折叠正方形纸片,使点
分别落到
边上的点
处,再展开,折痕为
,则点
在折痕
上吗?若在,请加以证明;若不在,请说明理由;
(3)如图3,在图2(隐去点
和
)的基础上,折叠正方形纸片,使点
分别落到点
处,再展开,折痕为
,折痕与
交于点
,连接,
,
,则
和
之间有何位置关系?并加以证明;
操作拓展
(4)如图4,该图中所有已知条件与图3完全相同,利用图4探索新的折叠方法(图3中产生折痕
的方法除外),找出与图3中点
位置相同的点,该点命名为
,要求只有一条折痕.请在图4中画出折痕和必要线段,标出点
,并简要说明折叠方法.(不需要说明理由)
问题情境
在综合与实践课上,老师组织同学们以“正方形纸片的折叠”为主题开展数学活动.请你解决活动过程中产生的下列问题.如图1,现有正方形纸片
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3557809c066e68395b614535a7675e76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
观察计算
(1)在图1中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84fb1afb48c74ad6e93f44cac5233211.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/18/1192c9a6-5a0e-4759-8e73-427fc8e6ce34.png?resizew=115)
操作探究
(2)如图2,在图1的基础上,折叠正方形纸片,使点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65436512ecbaefba4ac8123c55094211.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5fa8bd3792adb4f75697357808cd50c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b65d1919cf4bd397d396c60eed46d86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3557809c066e68395b614535a7675e76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/18/4b6b270f-39a5-4205-8121-8c6980ea156d.png?resizew=115)
(3)如图3,在图2(隐去点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2d7ffb7889a31b267a85f1ea238138e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19ae097a60b8859a0e6e8065041f2174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a64340f774b250e6d42d9dc1b127418.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/18/2ff5fd9a-a5ad-4101-bc46-0c67bc5d6af2.png?resizew=115)
操作拓展
(4)如图4,该图中所有已知条件与图3完全相同,利用图4探索新的折叠方法(图3中产生折痕
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ce066003c0a1f0879cbca2f32802e9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5d57d7dd861286e5ee6ec8dff0e19c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5d57d7dd861286e5ee6ec8dff0e19c5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/18/555cecc0-974c-4c86-8507-9af5667e3245.png?resizew=115)
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