如图,在侧棱锥垂直于底面的三棱柱ABC-A1B1C1中,AC=3,AB=5,BC=4,AA1=4,点D是AB中点,求证AC1∥面CDB1
人气:357 ℃ 时间:2019-10-17 01:28:26
解答
取A1B1中点,D1
连接AD1,C1D1,
C1D1//CD 所以 C1D1//平面CDB1
AD1//B1D 所以 AD1//平面CDB1
C1D1,AD1在平面AC1D1内
所以平面AC1D1//平面CDB1
AC在平面AC1D1内
所以 AC1∥面CDB1
推荐
- 如图,在直三棱柱ABC-A1B1C1中,AC=3,AB=5,BC=4,AA1=4,点D是AB的中点, (1)求证:AC⊥BC1; (2)求证:AC1∥平面CDB1. (3)求二面角C1-AB-C的正切值.
- 如图,在直三棱柱ABC—A1B1C1中,AC=3,BC=4,AB=5,AA1=4,点D是AB的中点.(Ⅰ)求证AC⊥BC1; (Ⅱ)求
- 3.如图,三棱柱ABC—A1B1C1中,AA1⊥面ABC,BC⊥AC,BC=AC=2,AA1=3,D为AC的中点.
- 如图,在直三棱柱ABC-A1B1C1中,AC=3,BC=4,AB=5,AA1=4,点D是AB的中点
- 如图所示,在三棱柱ABC-A1B1C1中,D点为棱AB的中点.求证:AC1∥平面CDB1.
- 已知某氧气和甲烷的混合气体在标况下对H2的相对密度为10,则混合气体在标况下的密度为?
- 已知123456789101112…997998999是由连续整数1至999排列组成的一个数,在该数中从左往右数第2013位上的数字为_.
- it's up
猜你喜欢
- I won't come to the party unless Peter_.
- 一个英语介词填空
- After the blind man had finished studying in the college,she found it very difficult to get a job.
- 敬畏的近义词
- please be c().there are many buses in the street.
- ___you happen to see Mary,would you please ask her to come here
- 〔1〕8分之 54化简 〔2〕-36分之3化简 〔3〕-0.3分之-6化简 ..
- shopping,would,you,go,like,to,me,with?连词成句 little,is,of,build,Gloria,medium.连词成句