题目
题型:不详难度:来源:
① 不共面的四点中,其中任意三点不共线;
② 若
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052741-58434.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052741-15853.png)
③ 对于四面体ABCD,任何三个面的面积之和都大于第四个面的面积;
④ 对于四面体ABCD,相对棱AB 与CD 所在的直线是异面直线;
⑤ 各个面都是三角形的几何体是三棱锥。
答案
解析
试题分析:对于① 不共面的四点中,其中任意三点不共线,成立。
对于② 若
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052741-82321.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052741-15853.png)
对于③ 对于四面体ABCD,任何三个面的面积之和都大于第四个面的面积,成立
对于④ 对于四面体ABCD,相对棱AB 与CD 所在的直线是异面直线;,成立
对于⑤ 各个面都是三角形的几何体是三棱锥,不一定还可能是正20面体,错误。故答案为3.
点评:解决该试题的关键是熟练的运用线面和线线的判定定理和性质定理来判定,属于基础题。
核心考点
试题【以下五个命题中,正确命题的个数是________.① 不共面的四点中,其中任意三点不共线;② 若∥;③ 对于四面体ABCD,任何三个面的面积之和都大于第四个面的】;主要考察你对线线角等知识点的理解。[详细]
举一反三
在四棱锥
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052722-53456.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052723-77452.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052723-75859.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052723-24296.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052723-56675.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052723-93444.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052723-82280.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052723-25127.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052724-38087.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052724-23132.png)
(I)证明:
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052724-58573.png)
(II)证明:
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052724-10919.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052725-87152.png)
(III)求二面角
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052725-35937.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052715-45930.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052715-62243.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052716-65106.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052716-19451.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
已知四棱锥
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052700-57274.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052700-36563.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052700-98474.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052700-23697.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052701-57551.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052701-96853.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052701-79039.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052701-85909.jpg)
(1)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052701-21935.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052701-96853.png)
(2)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052701-21935.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052701-79039.png)
如图,已知
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052648-91931.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052649-25346.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052649-25346.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052649-63432.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052649-30690.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052649-25346.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052649-63181.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052649-83724.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052649-59833.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052650-28088.jpg)
(1)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052650-72175.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052650-29467.png)
(2)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052650-89439.png)
(3)求三棱锥
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052650-67912.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052650-70593.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052637-59689.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052637-96262.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052637-66786.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052638-82206.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022052638-34450.png)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
最新试题
- 1将黑斑蛇与黄斑蛇杂交,子一代中既有黑斑蛇,又有黄斑蛇;若再将F1中的黑斑蛇与黑斑蛇交配,F2中既有黑斑蛇又有黄斑蛇。由此
- 2按如图所示装置进行下列不同的操作,其中不正确的是( )A.铁腐蚀的速度由大到小的顺序是:只接通K1>只闭合K3>都断开
- 3下边几何体的主视图是[ ]A.B.C.D.
- 4下列界线大致经过秦岭—淮河一线的是A.200mm等降水量线B.季风区与非季风区的分界线C.北方地区与南方地区的分界线D.
- 5(二)《画蛇添足》(6分)楚有祠①者,赐其舍人②卮③酒。舍人相谓曰:“数人饮之不足,一人饮之有余。请画地④为蛇,先成者饮
- 6“龙生龙,凤生凤,老鼠的儿子会打洞”这句谚语说明的生物现象是A.遗传B.变异C.生殖D.发育
- 7若a=3.0,则近似数a的取值范围是[ ]A. 2.95≤a≤3.05 B. 2.95≤a<3.05
- 8I _________ a basketball.[ ]A. play B. have C. wa
- 9对于A2 + 3B2 2C的反应来说,以下化学反应速率的表示中,反应速率最快的是A.v (B2) =" 0.8mol/
- 10—This book is ______ more useful for us students.—Yes, but i
热门考点
- 1仿照下面的示例,运用比喻修辞手法,自选诗人,仿写两个句子。高适诗是大漠沙场的一弯冷月,瑰丽雄健,黄沙、烽火、胡笳、弓刀,
- 2二元一次方程组的解满足2x-ky=10,则k的值等于[ ]A.4 B.-4 C.8
- 3They enjoyed_____ storybooks very much last year.A.to readB.
- 4经济理论界专家认为,从证券市场发展看,应对国有企业和非国有企业采取平等态度,私营企业上市对中国股票市场健康发展有重要意义
- 5读“地球五带分布示意图”,完成下列要求(9分)(1)写出图中字母代表的温度带名称:A____________带,气候
- 6下列实验操作的不正确的是( )A.用托盘天平称量药品时,先使天平平衡,后进行称量;B.点燃甲烷气体前,要先检验其纯度,
- 7十届全国人大四次会议《政府工作报告》高度关注民生问题,集中体现了新一届政府“执政为民”的理念。报告提出,五年内政府将投入
- 8以***为核心的党中央领导集体实际形成于[ ]A.中共十一大B.中共十一届三中全会C.中共十二大D.中共十三大
- 9上午4节课,一个教师要上3个班级的课,每个班1节课,都安排在上午,若不能3节连上,这个教师的课有______种不同的排法
- 10【题文】下列句子中“其”的意义和用法都相同的一项是( )①其孰能讥之乎