1. Enter To show the dynamic figures properly, the evaluation version of Cabri 3D (V2.0 or above) must be installed.

2. Enter There are 17 multiple choice questions. Click the letter to answer.

3. ABCDEFGH is a cuboid. Find the angle between DG and the plane ABCD. A  ADG B  BDG C  BGD D  CDG 1. (Hold down the right mouse button and drag to change the view angle.)

4. Hint: Click and right-button drag the figure to change the view angle. Find the angle between DG and the plane ABCD. Back 1. Incorrect!

5. Next The angle between DG and the plane ABCD is  BDG. (Hint: Click and right-button drag the figure to change the view angle.) 1. Correct!

6. ABCDEFGH is a cuboid. Find the angle between DG and the plane ADEF. B  EDG C  FDG A  BDG D  ADG 2. (Hold down the right mouse button and drag to change the view angle.)

7. Hint: Click and right-button drag the figure to change the view angle. Find the angle between DG and the plane ADEF. Back 2. Incorrect!

8. Next The angle between DG and the plane ADEF is  FDG. (Hint: Click and right-button drag the figure to change the view angle.) 2. Correct!

9. ABCD is a square, VO is the altitude of the pyramid. Find the angle between VB and the plane ABCD. B  OVB C  CBV A  OBV D  ABV 3. (Hold down the right mouse button and drag to change the view angle.)

10. 3. Incorrect! Hint: Click and right-button drag the figure to change the view angle. Find the angle between VB and the plane ABCD. Back

11. 3. Correct! Next The angle between VB and the plane ABCD is  OBV. ( Hint: Click and right-button drag the figure to change the view angle.)

12. ABCD is a square, M is the mid-point of BC, VO is the altitude of the pyramid. Find the angle between VM and the plane ABCD. B  BMV C  DMV A  AMV D  OMV 4. (Hold down the right mouse button and drag to change the view angle.)

13. 4. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between VM and the plane ABCD. Back

14. 4. Correct! Next The angle between VM and the plane ABCD is  OMV. (Hint: Click and right-button drag the figure to change the view angle.)

15. OABC is a triangular pyramid,  AOB = 90  ， CO is the altitude. Find the angle between AC and the plane OAB. B  OAC C  ABC A  OCA D  BAC 5. (Hold down the right mouse button and drag to change the view angle.)

16. 5. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between AC and the plane OAB. Back

17. 5. Correct ！ Next The angle between AC and the plane OAB is  OAC. (Hint: Click and right-button drag the figure to change the view angle.)

18. OABC is a triangular pyramid,  AOB = 90  ， CO is the altitude, P is a point on AB. Find the angle between CP and the plane OAB. B  OCP C  OAC A  OPC D  OBC 6. (Hold down the right mouse button and drag to change the view angle.)

19. 6. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between CP and the plane OAB. Back

20. 6. Correct ！ Next The angle between CP and the plane OAB is  OPC. (Hint: Click and right-button drag the figure to change the view angle.)

21. OABC is a triangular pyramid,  AOB = 90  ， CO is the altitude. Find the angle between CA and the plane OBC. B  OBA C  OAC A  BCA D  OCA 7. (Hold down the right mouse button and drag to change the view angle.)

22. 7. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between CA and the plane OBC. Back

23. 7. Correct ！ Next The angle between CA and the plane OBC is  OCA. (Hint: Click and right-button drag the figure to change the view angle.)

24. ABCDEF is a triangular prism, ABCD and CDEF are rectangles,  BCF = 90 . Find the angle between AE and the plane ABCD. B  AED C  BAE A  DAE D  CAE 8. (Hold down the right mouse button and drag to change the view angle.)

25. 8. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between AE and the plane ABCD. Back

26. 8. Correct ！ Next The angle between AE and the plane ABCD is  DAE. (Hint: Click and right-button drag the figure to change the view angle.)

27. ABCDEF is a triangular prism, ABCD and CDEF are rectangles,  BCF = 90 . Find the angle between AE and the plane CDEF. B  DAE C  AED A  AEB D  ADE 9. (Hold down the right mouse button and drag to change the view angle.)

28. 9. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between AE and the plane CDEF. Back

29. 9. Correct ！ Next The angle between AE and the plane CDEF is  AED. (Hint: Click and right-button drag the figure to change the view angle.)

30. ABCDEF is a triangular prism, ABCD and CDEF are rectangles,  BCF = 90 . Find the angle between AF and the plane ABCD. B  CAF C  BAF A  CFA D  DAF 10. (Hold down the right mouse button and drag to change the view angle.)

31. 10. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between AF and the plane ABCD. Back

32. 10. Correct ！ Next The angle between AF and the plane ABCD is  CAF. (Hint: Click and right-button drag the figure to change the view angle.)

33. ABCDEF is a triangular prism, ABCD and CDEF are rectangles,  BCF = 90 . Find the angle between AF and the plane CDEF. B  AFE C  AFC A  AFB D  AFD 11. ( Hold down the right mouse button and drag to change the view angle.)

34. 11. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between AF and the plane CDEF. Back

35. 11. Correct ！ Next The angle between AF and CDEF is  AFD. (Hint: Click and right-button drag the figure to change the view angle.)

36. ABCDEF is a triangular prism, ABCD and CDEF are rectangles,  BCF = 90 . Find the angle between AF and the plane ADE. B  FAD C  FAE A  FAC D  AFE 12. (Hold down the right mouse button and drag to change the view angle.)

37. 12. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between AF and the plane ADE. Back

38. 12. Correct ！ Next The angle between AF and the plane ADE is  FAE. (Hint: Click and right-button drag the figure to change the view angle.)

39. VABCD is a rectangular pyramid, ABCD is a rectangle, VD is the altitude. Find the angle between VC and the plane ABCD. B  VCB C  VCD A  VCA D  CVD 13. (Hold down the right mouse button and drag to change the view angle.)

40. 13. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between VC and the plane ABCD. Back

41. 13. Correct ！ Next The angle between VC and the plane ABCD is  VCD. (Hint: Click and right-button drag the figure to change the view angle.)

42. B  VBC C  VBD A  VAB D  BVD VABCD is a rectangular pyramid, ABCD is a rectangle, VD is the altitude. Find the angle between VB and the plane ABCD. 14. (Hold down the right mouse button and drag to change the view angle.)

43. 14. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between VB and the plane ABCD. Back

44. 14. Correct ！ Next The angle between VB and the plane ABCD is  VBD. (Hint: Click and right-button drag the figure to change the view angle.)

45. B  VCB C  VCD A  VCA D  CVD VABCD is a rectangular pyramid, ABCD is a rectangle, VD is the altitude. Find the angle between VC and the plane VAD. 15. (Hold down the right mouse button and drag to change the view angle.)

46. 15. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between VC and the plane VAD. Back

47. 15. Correct ！ Next The angle between VC and the plane VAD is  CVD. (Hint: Click and right-button drag the figure to change the view angle.)

48. B  BVD C  ABV A  AVB D  DBV VABCD is a rectangular pyramid, ABCD is a rectangle, VD is the altitude. Find the angle between VB and the plane VAD. 16. (Hold down the right mouse button and drag to change the view angle.)

49. 16. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between VB and the plane VAD. Back

50. 16. Correct ！ Next The angle between VB and the plane VAD is  AVB. (Hint: Click and right-button drag the figure to change the view angle.)

51. B  BVC C  BVD A  CBV D  DBV VABCD is a rectangular pyramid, ABCD is a rectangle, VD is the altitude. Find the angle between VB and the plane VCD. 17. (Hold down the right mouse button and drag to change the view angle.)

52. 17. Incorrect ！ Hint: Click and right-button drag the figure to change the view angle. Find the angle between VB and the plane VCD. Back

53. 17. Correct ！ End The angle between VB and the plane VCD is  BVC. (Hint: Click and right-button drag the figure to change the view angle.) Restart