如图1,线段AB、CD相交于点O,连结AD、CB,我们把这个图形称为“8字型”根据三角形内角和容易得到:∠A+∠D=∠C+∠B.
![](https://img.xkw.com/dksih/QBM/2018/6/6/1961571759071232/1967353820028928/STEM/15f110d69e524cb5ac43a71e571220d0.png?resizew=293)
![](https://img.xkw.com/dksih/QBM/2018/6/6/1961571759071232/1967353820028928/STEM/9a547c375b0d4798a6fcd8d03310766a.png?resizew=315)
(1)用“8字型”
如图2,∠A+∠B+∠C+∠D+∠E+∠F=___________;
(2)造“8字型”
如图3,∠A+∠B+∠C+∠D+∠E+∠F+∠G=_____________;
(3)发现“8字型”
如图4,BE、CD相交于点A,CF为∠BCD的平分
线,EF为∠BED的平分线.
①图中共有________个“8字型”;
②若∠B:∠D:∠F=4:6:x,求x的值.
![](https://img.xkw.com/dksih/QBM/2018/6/6/1961571759071232/1967353820028928/STEM/15f110d69e524cb5ac43a71e571220d0.png?resizew=293)
![](https://img.xkw.com/dksih/QBM/2018/6/6/1961571759071232/1967353820028928/STEM/9a547c375b0d4798a6fcd8d03310766a.png?resizew=315)
(1)用“8字型”
如图2,∠A+∠B+∠C+∠D+∠E+∠F=___________;
(2)造“8字型”
如图3,∠A+∠B+∠C+∠D+∠E+∠F+∠G=_____________;
(3)发现“8字型”
如图4,BE、CD相交于点A,CF为∠BCD的平分
线,EF为∠BED的平分线.
①图中共有________个“8字型”;
②若∠B:∠D:∠F=4:6:x,求x的值.
更新时间:2018-06-14 23:34:30
|
【知识点】 多边形内角和与外角和综合解读
相似题推荐
解答题-问答题
|
较难
(0.4)
【推荐1】如图 1,一张△ABC 纸片,点 M、N 分别是 AC、BC 上两点.
(1)若沿直线 MN 折叠,使 C 点落在 BN 上,则∠AMC′与∠ACB 的数量关系是 ;
![](https://img.xkw.com/dksih/QBM/2019/7/29/2257456844316672/2282114169741313/STEM/6ab2836ea1894c549e6e274c4d286433.png?resizew=349)
(2)若折成图 2 的形状.猜想∠AMC′、∠BNC′和∠ACB 的数量关系,并说明理由.
猜想: .
理由:
(3)若折成图3 的形状,猜想∠AMC′、∠BNC′和∠ACB 的数量关系是 .(写出结论即可).
(4)将上述问题推广,如图4,将四边形 ABCD 纸片沿 MN 折叠,使点 C、D 落在四边形 ABNM 的内部时,∠AMD′+∠BNC′与∠C、∠D 之间的数量关系 是 (写出结论即可).
(1)若沿直线 MN 折叠,使 C 点落在 BN 上,则∠AMC′与∠ACB 的数量关系是 ;
![](https://img.xkw.com/dksih/QBM/2019/7/29/2257456844316672/2282114169741313/STEM/6ab2836ea1894c549e6e274c4d286433.png?resizew=349)
(2)若折成图 2 的形状.猜想∠AMC′、∠BNC′和∠ACB 的数量关系,并说明理由.
猜想: .
理由:
(3)若折成图3 的形状,猜想∠AMC′、∠BNC′和∠ACB 的数量关系是 .(写出结论即可).
(4)将上述问题推广,如图4,将四边形 ABCD 纸片沿 MN 折叠,使点 C、D 落在四边形 ABNM 的内部时,∠AMD′+∠BNC′与∠C、∠D 之间的数量关系 是 (写出结论即可).
![](https://img.xkw.com/dksih/QBM/2019/7/29/2257456844316672/2282114169741313/STEM/7eadc4fd4d854055b8c6e74dafa1abba.png?resizew=365)
您最近一年使用:0次
解答题-问答题
|
较难
(0.4)
【推荐2】如图,
在平面直角坐标系中,
,
,
,点
、
在
轴上且关于
轴对称.
![](https://img.xkw.com/dksih/QBM/2020/3/3/2411843473276928/2412343615053824/STEM/8405534ea9ea4c29af72a826ae854cd8.png?resizew=198)
(1)求点
的坐标;
(2)动点
以每秒2个单位长度的速度从点
出发沿
轴正方向向终点
运动,设运动时间为
秒,点
到直线
的距离
的长为
,求
与
的关系式;
(3)在(2)的条件下,当点
到
的距离
为
时,连接
,作
的平分线分别交
、
于点
、
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b57fdd2a3642716fcf5100011eb3ec88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dcb761f211aa7c1eafb2fde13890cf4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54275b7e571660d0a9e0370fbfe5050b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://img.xkw.com/dksih/QBM/2020/3/3/2411843473276928/2412343615053824/STEM/a41fa7a1dc6348ce9b7638b4ff76f7d5.png?resizew=195)
![](https://img.xkw.com/dksih/QBM/2020/3/3/2411843473276928/2412343615053824/STEM/8405534ea9ea4c29af72a826ae854cd8.png?resizew=198)
![](https://img.xkw.com/dksih/QBM/2020/3/3/2411843473276928/2412343615053824/STEM/8405534ea9ea4c29af72a826ae854cd8.png?resizew=198)
(1)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)动点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
(3)在(2)的条件下,当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adbd3e8cf8325999cde03adf845d3dd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fabb884dc5f9609de491245463bbe9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
您最近一年使用:0次