如图,AD、AE分别是△ABC的角平分线和高,∠B=50°,∠C=70°,求∠ADE和∠DAE的度数.
![](https://img.xkw.com/dksih/QBM/2020/11/13/2592005094825984/2604260448288768/STEM/8011bb6e-a0f0-4da8-9efe-92d1675a337c.png)
更新时间:2020-11-30 20:04:21
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
【推荐1】如图-1,P是等腰三角形ABC底边BC上的一个动点,过点P作BC的垂线,交AB于点Q,交CA的延长线于点R.
(1)请观察AR与AQ,它们有何关系?并证明你的猜想.
(2)如果点P沿着底边BC所在的直线,按由C向B的方向运动到CB的延长线上时,(1)中所得的结论还成立吗?请你在图-2中完成图形,并给予证明.
(1)请观察AR与AQ,它们有何关系?并证明你的猜想.
(2)如果点P沿着底边BC所在的直线,按由C向B的方向运动到CB的延长线上时,(1)中所得的结论还成立吗?请你在图-2中完成图形,并给予证明.
![](https://img.xkw.com/dksih/QBM/2020/11/1/2583733858394112/2596552635727872/STEM/9f5b29c1-f226-40a8-9887-9de3dabce53a.png)
您最近一年使用:0次
解答题-作图题
|
适中
(0.65)
【推荐2】如图,已知:在
中,
,
于点D.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/30/32ec8b12-4b0f-4e14-b5fb-a2c7fd4f9739.png?resizew=150)
(1)尺规作图:作线段
的垂直平分线交
于点E,交
于点F,连接
(不写作法,保留作图痕迹);
(2)求证:
.
证明:∵
,
∴
① ,
∵
是
的垂直平分线,
∴
② ,
∴
,
∴
,
即
③ ,
∵
,
∴ ④
,
∴
,
∴
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70734a8e672376bb0bd1522e229f86a2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/30/32ec8b12-4b0f-4e14-b5fb-a2c7fd4f9739.png?resizew=150)
(1)尺规作图:作线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92e06268afbd3701864038813c3e44be.png)
证明:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4db07c6ce6c8b0e96a3470c6a3491334.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd7fa9d70f03e1206629649addd8dddc.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe86f847b4da613c90a7bdefcd994006.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af015f7ef349e2fc46a703ff6020e247.png)
即
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/863c4a2e68dae7f51ae92052e830f73b.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70734a8e672376bb0bd1522e229f86a2.png)
∴ ④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/475ff337241b4234463c699219007738.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/838165d7e5f450e45e0ac29c608f0dc1.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92e06268afbd3701864038813c3e44be.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】如图,点P是
的内角平分线
与
的交点,点M是
的外角平分线
与
的交点,则
.
说明
如下,
∵
,
是
的角平分线,
∴
,
,
∴
,①
∴
,
∴
.
请你仔细阅读理解上面的说明过程,完成下列问题:
(1)上述说明过程中步骤①的依据是_______________.
(2)结合下图,证明
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db54223bb3fc2fe2497213a4d1f94827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82d3b556fd4e10d90418ab4d0541a925.png)
说明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82d3b556fd4e10d90418ab4d0541a925.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79c1c28a7e5fbd1008e3de19dfd76cb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca4bfcfb47efdcc79836922ff8a58e72.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d77e66e02810dd70f784405a744a29c5.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47b3fb0a8cf40c14c7881be6f08e77c1.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96eec4dcc11e2cd6a41f47bb0e83207a.png)
请你仔细阅读理解上面的说明过程,完成下列问题:
(1)上述说明过程中步骤①的依据是_______________.
(2)结合下图,证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6fafa2008d7e9e84b2cbfd3e36c81be.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/16/21dbf600-6044-4f13-984f-924d9561f16e.png?resizew=143)
您最近一年使用:0次
【推荐2】在
中,BE,CD为
的角平分线,BE,CD交于点F.
(1)求证:
;
(2)已知
.
①如图1,若
,
,求CE的长;
②如图2,若
,求
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f572ff50ee2c78feabb427259a4be499.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5b8b98b2f83279a49e94d9f48c5e6f2.png)
①如图1,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7eb3d1070981fed5ca65a34bb2282e6f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9b9ff460cbb35ba8ad10b17513f1de4.png)
②如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe8bb808edb7f81fb3c14c8f3d7f0fad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a55a1a244f81097e05e715b69580faa.png)
![](https://img.xkw.com/dksih/QBM/2021/11/3/2843166526717952/2845481373515776/STEM/0ad0e613-0446-46d9-aaf3-3ccb813dec15.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
【推荐3】如图,点A、B分别在射线OM、ON上运动(不与点O重合).
![](https://img.xkw.com/dksih/QBM/2019/8/5/2262249786720256/2262420323516416/STEM/e2ff50d26279476c8a8e45e00902674b.png?resizew=471)
(1)如图1,若∠MON=90°,∠OBA、∠OAB的平分线交于点C,则∠ACB= °;
(2)如图2,若∠MON=n°,∠OBA、∠OAB的平分线交于点C,求∠ACB的度数;
(3)如图2,若∠MON=n°,△AOB的外角∠ABN、∠BAM的平分线交于点D,求∠ACB与∠ADB之间的数量关系,并求出∠ADB的度数;
(4)如图3,若∠MON=80°,BC是∠ABN的平分线,BC的反向延长线与∠OAB的平分线交于点E.试问:随着点A、B的运动,∠E的大小会变吗?如果不会,求∠E的度数;如果会,请说明理由.
![](https://img.xkw.com/dksih/QBM/2019/8/5/2262249786720256/2262420323516416/STEM/e2ff50d26279476c8a8e45e00902674b.png?resizew=471)
(1)如图1,若∠MON=90°,∠OBA、∠OAB的平分线交于点C,则∠ACB= °;
(2)如图2,若∠MON=n°,∠OBA、∠OAB的平分线交于点C,求∠ACB的度数;
(3)如图2,若∠MON=n°,△AOB的外角∠ABN、∠BAM的平分线交于点D,求∠ACB与∠ADB之间的数量关系,并求出∠ADB的度数;
(4)如图3,若∠MON=80°,BC是∠ABN的平分线,BC的反向延长线与∠OAB的平分线交于点E.试问:随着点A、B的运动,∠E的大小会变吗?如果不会,求∠E的度数;如果会,请说明理由.
您最近一年使用:0次