1 . 在正
的平面内有任一点
(不在
的三条高线所在直线上),点
关于直线
、
、
的对称点为
,
、
.证明:
的外心在一条直线上.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5614fbac899088deaed1298a62e2ff5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5614fbac899088deaed1298a62e2ff5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f445af60a2950f1bf61ab76c8682451c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d48101bb735f309819728150e20d57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bc9076974ebd6331d67055302be8167.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b9cb8e6ff801523b0304576cd69fd2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/797e67927616b141ed7c6b83f8b6f4fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/066b8e635cc02acb2cb541429157cd28.png)
您最近一年使用:0次
2 . 已知
为任意凸四边形.分别以
、
为边在四边形外作正
和正
,以
、
为底边在四边形外作顶角为
的等腰三角形
和
.求证:
,且
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88929f4ba0851730d5f941d426b87548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e34a9667453c05bc78de93ba5313e734.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59b0c3bc854308c01e4a8bb5e0995620.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ffb98f1e3c1317c0db403d3af04bdc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84288b493b64c3a30466fb9075621da4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fa485cf3776f36aaf4abaadaf30fb85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d01f6f70b5cb3fd3b580e9f298588d6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dfa17ce4597d93782a605b929c55e8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf491301d68ddc4951dd5a321c2c91f7.png)
您最近一年使用:0次
3 . 已知圆内接六边形ABCDEF的末尾两位数字是的边满足关系式AB=CD=EF=r,r为圆的半径,G、H、K分别是边BC、DE、FA的中点.试说明△GHK是否为正三角形.
您最近一年使用:0次