题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233417-68727.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233417-63207.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233417-32693.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233418-49958.png)
A.垂心 | B.外心 | C.内心 | D.重心 |
答案
解析
试题分析:因为三个侧面两两垂直,所以
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233418-52346.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233418-52346.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233418-14363.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233417-63207.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233417-68727.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233418-12611.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233418-97510.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233419-87897.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233419-84751.png)
点评:本题需要掌握好三角形的各种“心”。
核心考点
试题【三棱锥的高为,若三个侧面两两垂直,则一定为△的( )A.垂心 B.外心C.内心D.重心】;主要考察你对空间几何体的结构特征等知识点的理解。[详细]
举一反三
如图,在四棱柱
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233401-17053.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233401-96376.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233401-62110.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233402-42539.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233403-85569.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233403-88675.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233403-94333.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233403-84885.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233403-21408.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233404-13339.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233404-16957.png)
(1)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233404-62925.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233404-37856.png)
(2)求直线
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233404-28798.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233404-76438.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233353-55054.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233345-46647.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233345-88396.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233345-39898.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233345-72306.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233346-82537.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233346-36921.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233346-11011.png)
(1)求直线PB与平面PDC所成的角的正切值;
(2)求二面角A-PB-D的大小.
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233330-23000.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233330-37774.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233331-65076.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233331-10684.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233309-78082.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233309-40796.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233309-22411.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233309-22411.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233309-40052.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233309-88710.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233310-71607.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233310-80551.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233310-67483.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233310-60813.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233310-43412.png)
(1)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233311-45965.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233311-14414.png)
(2)求直线
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233311-62583.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020233311-14414.png)
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