Cho lăng trụ đứng  có diện tích tam giác  bằng  . Gọi  lần lượt thuộc các cạnh  và diện tích tam giác  bằng 10. Tính góc giữa hai mặt phẳng  và .        

Chia sẻ

Một số câu hỏi khác có thể bạn quan tâm.

• Choose the best answer for the following sentence:

  It _____________ possible for me to continue playing tennis since I ____________ school.

   

• Choose the best answer for the following sentence:

  ______________ months have been very trying.
   

• Choose the best answer for the following sentence:

  One of our difficulties is we do not always have the ____________ addresses of all our members.
   

• Choose the best answer for the following sentence:

  _____________ that's happened is a waste of time.
   

• Choose the best answer for the following sentence:

  I don't think ______________ knows ____________ about it.
  

• Choose the best answer for the following sentence:

  Most of people would like, ___________ to read faster.
   

• Choose the best answer for the following sentence:

  I admired him ____________ his acting beautifully.
  
  

• Choose the best answer for the following sentence:

  President Kennedy __________ when he __________ through Dallas.
   

• Choose the best answer for the following sentence:

  Some of the proposals ___________ .
   

• Choose the word that has the underlined part pronounced differently from the rest:

  appropriate                                 approach                                     attitude                            attraction