题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211605-73065.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211605-99490.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211605-58732.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211605-50279.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211605-69090.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211605-15400.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-70817.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-97433.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-74052.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-29280.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-14559.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-10485.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-45376.png)
(1)判断
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-99150.png)
(2)当
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-47466.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-97433.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-61361.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211605-69090.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-36359.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-10213.png)
(3)当
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-10213.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-82689.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-74559.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-65801.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-97433.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211606-61361.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211605-69090.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-36359.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-25661.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-34213.png)
解析
试题分析:(1)根据旋转的性质可得PB=PC,∠PBC=90°,故△PBC是等腰直角三角形;
(2)以P、O、B、C为顶点的四边形为平等四边形:因为
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-71794.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-86532.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-86255.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-87837.png)
(3)由题意可知,
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-71269.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-96649.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-82689.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-74559.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-10875.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-41190.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-69714.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-82689.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-10365.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-89923.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211609-19993.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211609-69456.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-34213.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-82689.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-10365.png)
试题解析:(1)△PBC是等腰直角三角形.
∵线段PB绕着点P顺时针方向旋转90°,得到线段PC
∴PB=PC,∠BPC=90°,
∴△PBC是等腰直角三角形.
(2)当OB⊥BP时,以P、O、B、C为顶点的四边形为平行四边形.
∵∠OBP=∠BPC=90°
∴OB∥PC,
∵B是PA的中点
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211609-95323.png)
∴四边形POBC是平行四边形
当OB⊥BP时,有
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-86532.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-86255.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-87837.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211609-80811.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211609-66890.png)
∴当t=2时,以P、O、B、C为顶点的四边形为平行四边形.
(3)由题意可知,
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-71269.png)
当
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-96649.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-82689.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-74559.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-10875.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-41190.png)
当
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-69714.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-82689.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-10365.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-89923.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211609-19993.png)
∴当
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211609-69456.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-34213.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211607-82689.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211608-10365.png)
考点: 1.等腰直角三角形的判定;2.平等四边形的判定;3.相似三角形的判定与性质.
核心考点
试题【如图,在平面直角坐标系中,点的坐标为,点在轴上,是线段的中点.将线段绕着点顺时针方向旋转,得到线段,连结、.(1)判断的形状,并简要说明理由;(2)当时,试问:】;主要考察你对相似图形等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211551-70241.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211551-12089.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211546-96399.jpg)
(1)如果P、Q分别从A、B两点同时出发,经过几秒钟,△PBQ的面积等于8厘米2?
(2)如果P、Q两分别从A、B两点同时出发,并且P到B又继续在BC边上前进,Q到C后又继续在CA边上前进,经过几秒钟,△PCQ的面积等于12﹒6厘米2 ?
A.矩形与矩形 | B.正方形与菱形 | C.菱形与菱形 | D.正方形与正方形 |
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102211537-54989.jpg)
A.![]() | B.![]() | C.![]() | D.![]() |
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