【简答题】下面一组图形为三棱锥 P - ABC 的底面与三个侧面.已知 AB ⊥ BC , PA ⊥ AB , PA ⊥ AC . (1)在三棱锥 P - ABC 中,求证:平面 ABC ⊥平面 PAB ; (2)在三棱锥 P - ABC 中, M 是 PA 的中点,且 PA = BC =3, AB =4,求三棱锥 P - MBC 的体积.
【简答题】A.She is a foreign student staying in Britain. B.Her room is a little expensive, but she can save a great deal' on transportation. C.She spent a lot on traveling. D.The total time spent on a part-time...