如图,CD平分∠ECF,∠B=∠ACB,求证:AB∥CE.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/10/8412ff79-3ba4-4333-9008-abebf8552edc.png?resizew=247)
更新时间:2019-05-22 13:17:37
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
【推荐1】已知:如图,直线
相交于点
为射线,且
平分
.
(1)求
的度数;
(2)请直接写出图中4对相等的角(直角、平角除外).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c28d2790a97390935125aa897417f970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a284f6ac17cea6e74d30fbcaad39823.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca7afe853e98928d7977283c52c9120f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5eba08873c947fb391060d723f2154a6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/29/f8956900-d1c4-46db-b703-e8afe1d72094.png?resizew=153)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21a52e349973e2c589b48066c9068a8e.png)
(2)请直接写出图中4对相等的角(直角、平角除外).
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】如图,已知
,点A、B在直线a上,点C、D在直线b上,且
于点E.
(1)求
的度数;
(2)在图1上作
平分
交
于点F,
平分
交
于点G,如图2,求
的度数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8a4352562ae8aa968014fd0d931b677.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5f215a42c4b7078d8d65923eb9980e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/28/9f11daab-12d0-4551-a10e-6ab4bb6c7687.png?resizew=506)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca4678ff1b3ea3bd09ed3494a0efe31c.png)
(2)在图1上作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/060705794ef87cc71dac40c57f27b1d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3db3f03c05b28155f9c0d31abfab198.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3950afe34a592ec6c672e9d3dd81252.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】请完成下列证明:如图,已知
.求证:
.
证明:∵
(已知)
∴
_____(垂直的定义)
∴
(______)
∴______
(______)
∴
______(______)
又∵
(已知)
∴
(等量代换)
∴
(______)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab06dce5c6b6df933ce8280d6a9a5f59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c21d1a73e978f0e03070a26793eefdc5.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dff6bd71cef72338de3b461ebac21079.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48131ee897edea76a4086aa1b7adebf7.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1156d17d1294f0bcb54beb045ef6fdd2.png)
∴______
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13a83e7ca69f682b0a94683ab914393c.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/494ba20b1444f524cf636961e4688ae8.png)
又∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e53497af8899cb299d762f1a4f46a55.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c8d5b57d85da29b7d57df3fc3dc5a85.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c21d1a73e978f0e03070a26793eefdc5.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】如图,四边形ABCD中,∠A=∠C=90°,BE平分∠ABC交CD于E,DF平分∠ADC交AB于F.
(1)若∠ABC=50°,则∠ADC= °,∠AFD= °;
(2)BE与DF平行吗?试说明理由.
(1)若∠ABC=50°,则∠ADC= °,∠AFD= °;
(2)BE与DF平行吗?试说明理由.
![](https://img.xkw.com/dksih/QBM/2017/3/17/1645661708427264/1654384866549760/STEM/825f28ddf43540ceb6533c5928ad4053.png?resizew=182)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】在古代,智慧的劳动人民已经会使用“石磨”,其原理为在磨盘的边缘连接一个固定长度的“连杆”,推动“连杆”带动磨盘转动,将粮食磨碎,物理学上称这种动力传输工具为“曲柄连杆机构”.晓晓受此启发设计了一个“连杆机构”,设计图如图1所示,
为一根固定长度的连杆,通过一端A在直线l上滑动,使得点B带动
绕圆心O转动,当连杆
恰好经过圆心O时,如图2所示,此时记
与
的另一个交点为C,过点B作
交直线l于点D,发现
恰好平分
.
相切;
(2)若
,
,求
的半径.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b455b110a30c1533d0a0657e0e48ac33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71b63d2504bd3ecce8c10560b142356f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/868ff1350bd72625328c85c3097cd85e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432cce1481829c4dfe2bd557f6e9aa4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18b5e7ad8fde2001e99ae54838adb9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图1,
、
是
的外角平分线,过点A分别作
,
,垂足分别为F,G,连接
,延长
,
.与直线
分别交于点M,N.
(1)试说明:
.
(2)如图2,若
、
是
的内角平分线,则线段
的长与
的三边长之间又有怎样的数量关系?请写出你的猜想并证明.
(3)如图3,若
为
的内角平分线,
为
的外角平分线,则线段
的长与
的三边长之间的数量关系是______.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e39b13d187b25461d85a3b8d10c7b678.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6813488bd1ea40a3aa5e2cb3be7bf312.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/21/d20f664d-9b61-4aff-a87e-6081bb6d4222.png?resizew=222)
(1)试说明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bdd8edd1e9f60727fc836b4f7b12a31.png)
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/21/a1d093aa-4526-4c86-8b00-84593ff9d593.png?resizew=193)
(3)如图3,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c63e36329f5e0979f5ee776ac5d06327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/21/fda8f733-e3d0-4cfe-a7b3-a5a111c200b6.png?resizew=213)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐3】【问题背景】在学习了等腰三角形等有关知识后,数学活动小组对如图所示的课本上的一道例题进行了深入探究,发现:当角平分线遇上平行线时一般可得等腰三角形,有角平分线时,常过角平分线上一点作角的平行线构造等腰三角形.如图1,P为∠AOB的角平分线OC上一点,过点P作PD∥OB交OA于点D,易证△POD为等腰三角形.
【基本运用】(1)如图2,把长方形纸片ABCD沿对角线AC折叠,点B落在点B'处,重合部分△ACE是等腰三角形吗?为什么?
【类比探究】(2)如图3,△ABC中,∠ABC的角平分线BO与外角∠ACG的角平分线交于点O,过点O作OD//BC分别交AB、AC于点D、点E,试探究线段BD、DE、CE之间的数量关系并说明理由;
【拓展提升】(3)如图4,四边形ABCD中,AD∥BC,E为CD边的中点,且AE平分∠BAD,连接BE,求证:AE⊥BE.
【基本运用】(1)如图2,把长方形纸片ABCD沿对角线AC折叠,点B落在点B'处,重合部分△ACE是等腰三角形吗?为什么?
【类比探究】(2)如图3,△ABC中,∠ABC的角平分线BO与外角∠ACG的角平分线交于点O,过点O作OD//BC分别交AB、AC于点D、点E,试探究线段BD、DE、CE之间的数量关系并说明理由;
【拓展提升】(3)如图4,四边形ABCD中,AD∥BC,E为CD边的中点,且AE平分∠BAD,连接BE,求证:AE⊥BE.
![](https://img.xkw.com/dksih/QBM/2021/12/9/2868884454244352/2869335746977792/STEM/250f63b6-3db3-416f-ae12-4b75fc4ae9bf.png?resizew=610)
您最近一年使用:0次