如图1,长方形ABCD沿着直线DE和EF折叠,使得AB的对应点
和点E在同一条直线上.
(1)求∠DEF的度数;
(2)如图2,若再次沿着直线EM和EN折叠使得A、B的对应点
分别落在DE和EF上,∠AEM=34°,求∠BEN的度数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e96973d5dcee48a6847c3209be1597.png)
(1)求∠DEF的度数;
(2)如图2,若再次沿着直线EM和EN折叠使得A、B的对应点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8669d3478a7bdcb89ba09e0b67044ffe.png)
![](https://img.xkw.com/dksih/QBM/2019/1/30/2129951463972864/2166952033927169/STEM/04cf64a62502474dae1e48cc87647ca1.png?resizew=304)
18-19七年级上·福建莆田·期末 查看更多[2]
更新时间:2019-03-23 23:38:06
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】操作与思考 折纸的思考
操作:折出含
角的直角三角形.
如图①,准备一张正方形纸片![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
第一步,对折正方形纸片
,使
与
重合,得到折痕
,把纸片展平(如图②),第二步,如图③,再一次折叠纸片,使点C落在
上的P处,并使折痕经过点B,得到折痕
,通过测量,发现
,请你说明理由.
探索:含
角的直角三角形的性质
(1)剪下图③中的直角
纸片,度量
的长度,发现
的数量关系是
;
(2)猜想结论:直角三角形中,
角所对直角边等于斜边的一半;
(3)验证:按照下图进行折叠:折叠
,使B与H重合,得到折痕
,如图④,请你利用图④证明猜想的正确性.
操作:折出含
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
如图①,准备一张正方形纸片
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
第一步,对折正方形纸片
![](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/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdae78f4d3b8d8213ac3ac9a9567eb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bda8d97801df2f62df6d3612eb2c1c02.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/18/dc0a52f3-d3dd-4a2d-80ad-b97109ed57f8.png?resizew=376)
探索:含
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
(1)剪下图③中的直角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6629fbe2eef7def1afa88acbbabdb10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b0242495bc42b24b5841eabf717dfd3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b0242495bc42b24b5841eabf717dfd3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3238359fb4ecfb74c9e69c0434dffa19.png)
(2)猜想结论:直角三角形中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
(3)验证:按照下图进行折叠:折叠
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6629fbe2eef7def1afa88acbbabdb10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/18/291c898e-49ad-4e0f-ad5b-ef5dcb58777f.png?resizew=270)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】在
中,
,点
是
上一点,将
沿
翻折后得到
,
交
于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/14/422aecc6-b031-4d90-a28b-68e406e73388.png?resizew=179)
(1)如图1,当
时,证明:
;
(2)已知
,设
.
①如图2,当
时,求
的值.
②如图3,当
是等腰三角形时,求出
的值.
![](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/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c771a4feb150ad9cff8d70431c97eb17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/14/f1d27d1f-166c-4365-91ab-8932ef8b3370.png?resizew=158)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/14/342449e0-5067-4cc9-ad6a-9d95e4453acc.png?resizew=176)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/14/422aecc6-b031-4d90-a28b-68e406e73388.png?resizew=179)
(1)如图1,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e3f5dc11efe60b4fd9a13b1d6b83842.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/105068b25f5a63af32f4082cfe08691e.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/640e9e7c56e8eeda044fb55396088816.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f13be03c1a7cbd8b9c8ebbfd914b1d81.png)
①如图2,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bffd657e48b15b9b54a55817e2c26b22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
②如图3,当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72cb97395ebc5ee1b212afb7a97b985c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
您最近一年使用:0次