如图所示,在
中,
平分
,点
为线段
上的一个动点,
交
的延长线于点E.若
,
,求
的度数.
∵
(已知),
( ),
∴
( ),
.
∵
平分
(已知),
∴
( ),
.
∴
( ),
.
∵
(已知),
∴
( ).
在直角三角形
中,
∵
( ),
∴
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d603566c74b1d5de510a2e8f7859010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19766bbdc2d23ae20e9f34530c3a1543.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe6ae03541d04b569ee9177384c0bbc2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b871a762469393cdd22f15aa49ebb8f9.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec4c5b4492ca00b1c799b96ab094fb68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c383dc85cff44ee63ee694377c876b7c.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f073cf17036c8eb89d9add87cd469218.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d86f48ca3301c7c28370809ce61204d9.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbce11aa19b8bd2bf6ee5a834e005de.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8c94202165ced962abf3aba10911352.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfd8c2b720184cff347e58cb973e028e.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cf23104e122c3d9ccf2453ab0049a1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6746e97ca796dba64da903c55456305.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d603566c74b1d5de510a2e8f7859010.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8d9060d7c8359fefd0cfd0d2d75197c.png)
在直角三角形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96d7678c323b61e6ac3f57e4c53456a9.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0a06445a4b487a3e05a5c9483650f13.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d618e730ea435656ee2926419b26d516.png)
更新时间:2024-05-22 09:39:51
|
相似题推荐
解答题-计算题
|
适中
(0.65)
【推荐1】在某山区需要修建一条高速公路,在施工过程中要沿直线
打通一条隧道,动工前,应先测隧道
的长,现测得
,
,
,请根据上述数据,求出隧道
的长(计算结果保留根号).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
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您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,在
中,
,
,点
是射线
上一点,
,过点
作
,垂足为
,
与
的延长线相交于点
.
![](https://img.xkw.com/dksih/QBM/2021/11/16/2852652169396224/2867988111294464/STEM/6dc1e9b1-5393-42c8-85e1-e5c31ec5909e.png?resizew=310)
(1)求证:
;
(2)过点
作
,过点
作
,垂足为
,探究
与
的数量关系,并证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abcb980da8e86b4cfd322616dc84fc6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c42ed2e5bd5a0f033e24008697bf4963.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fc1a7ac08428440f64dd640e03716ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80537d6b40787641ea2e59df6d1dbb50.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.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/8455657dde27aabe6adb7b188e031c11.png)
![](https://img.xkw.com/dksih/QBM/2021/11/16/2852652169396224/2867988111294464/STEM/6dc1e9b1-5393-42c8-85e1-e5c31ec5909e.png?resizew=310)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56ee81929c987732fcb379802eeef7a7.png)
(2)过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2e36fe861dbf3d8e285110a283c4c61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faa4987b733da847eefdf1a84eb5a633.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e4fa04825ac7d071968056322d88be.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】在学习了角平分线的性质后,小明想要去探究直角梯形的两底边与两非直角顶点所连腰的数量关系,于是他对其中一种特殊情况进行了探究:在直角梯形
中,
,
平分
交
于点E,连接
,当
平分
时,探究
、
与
之间的数量关系.他的思路是:首先过点E作
的垂线,将其转化为证明三角形全等,然后根据全等三角形的对应边相等使问题得到解决.请根据小明的思路完成下面的作图与填空:
证明:用直尺和圆规,过点E作
的垂线,垂足为点F.(只保留作图痕迹)
∵
,
∴
,
∵
平分
,
,
∴ (角平分线的性质),
在
和
中,
∵
,
∴
.
∴ ,
同理可得:
,
∴
,
即
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7d8397018b0a01a1b4e9574604f9e76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2947ca8e0cdbeb4aab80ce9e7b63ba98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3981e7286d41960daf4e110c1c84e03a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/4/503249a5-e5d8-4232-a38c-a680c4e3d190.png?resizew=150)
证明:用直尺和圆规,过点E作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60d9142db4dd2ef151bf3d4a63afb61e.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7672022057a656c5638e6e384dc630cc.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2947ca8e0cdbeb4aab80ce9e7b63ba98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab1a1fd2fc33e89f357cef772ff6cd0e.png)
∴ (角平分线的性质),
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1a3b94566843e92ce775ff6bdf386fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1944b717d04b665fce6e5d3c51d569ab.png)
∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3967cf7c40fbebc30c45998b8fb656da.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f6d6a2afe2fcf8ef3df23f3a08f2e44.png)
∴ ,
同理可得:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4c91348119d864bf3e59098e837abd1.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc849d01c4e853b9ebcfacc40fc1ddf5.png)
即
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6feb71636e2e0482de54134eadad0ec8.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,已知
的角平分线
与
边的垂直平分线相交于点
,过点
分别作
的垂线,垂足分别为点
.求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0d54431bbb28ebd98db5c1dc6083a75.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f805768a5ffaf8bdfa4bc3b680aafdc9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/13/b50a529f-566b-40e6-9bab-931100fffdaa.png?resizew=146)
您最近一年使用:0次