题目
题型:不详难度:来源:
A.∠A∶∠B∶∠C = 1∶1∶2 | B.a∶b∶c =1∶1∶![]() |
C.![]() | D.∠A+∠B=2∠C |
答案
解析
试题分析:在△ABC中,∠A,∠B,∠C的对边分别是a,b,c,选项A,∠A∶∠B∶∠C = 1∶1∶2 ,∠A+∠B+∠C=
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105125-83699.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105125-69635.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105125-71889.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105126-37669.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105125-69635.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105125-31893.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105126-67467.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105126-13480.png)
,∠A+∠B+∠C=
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105125-83699.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105127-96635.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105127-87660.png)
点评:本题考查直角三角形,解本题需要考生掌握直角三角形的判定方法,利用角,边的关系从而来判定是否是直角三角形
核心考点
试题【在△ABC中,∠A,∠B,∠C的对边分别是a,b,c,满足下列条件的△ABC 不是直角三角形的是( )A.∠A∶∠B∶∠C = 1∶1∶2B.a∶】;主要考察你对点、线、面、体等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105120-24267.png)
①两条直线平行,同旁内角互补
②同位角相等,两直线平行
③内错角相等,两直线平行
④同一平面内,垂直于同一直线的两直线平行
A.① | B.②和③ | C.④ | D.①和④ |
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105114-78882.png)
(1)若∠AMN=50º,∠EPN=70º,分别求∠MNP,∠DNQ的度数;
(2)若∠AMN=
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105114-51969.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105114-56291.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105114-51969.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105114-56291.png)
(3)试探究:∠DNQ与∠AMN,∠EPN之间的数量关系,并说明理由.
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105104-28705.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105105-80695.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105105-18700.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105105-25757.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105056-72844.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105056-69136.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105056-29332.png)
小明同学的解答如下:如图1所示,过点
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105056-92370.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105057-40941.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105057-83508.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105057-11425.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105057-39126.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105057-50966.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105057-60826.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105058-78577.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105058-25806.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105058-61192.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105058-64196.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105059-14572.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105059-13303.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105059-40973.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105059-82079.png)
(1)请你参考小明的作法,在图2中作一个等腰直角三角形
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105059-36388.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105056-29332.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105100-76862.png)
(2)若直线
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105100-98920.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105100-84469.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105100-31767.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021105101-97049.png)
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