Please answer the following question.?

2017-03-16 12:21 am

https://www.flickr.com/photos/124898006@N08/32614562804/in/dateposted-public/

In addition, according to the model answer, if M is the mid-point of AB, the triangle VMD is a right-angled triangle, do you agree, please prove.

Thank you very much

回答 (1)

2017-03-18 7:59 am

✔ 最佳答案

angle ABC=90 & angel VBC=90 --> plane VAB is perpendicular to plane ABCD, then you can solve the question.

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