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

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

3. 1. (Hold down the right mouse button and drag to change the view angle.) ABCDEFGH is a cuboid. Find the projection of DG on the plane ABCD. ABC BBD CBG DAD

4. 1. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from G to the plane ABCD? Back

5. 1. Correct! Next The projection of DG on the plane ABCD is BD. (Click and right-button drag the figure to change the view angle. )

6. ABCDEFGH is a cuboid. Find the projection of DG on the plane ADEF. BDE CDF AFG DAD 2. (Hold down the right mouse button and drag to change the view angle.)

7. 2. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from G to the plane ADEF? Back

8. 2. Correct! Next The projection of DG on the plane ADEF is DF. (Click and right-button drag the figure to change the view angle. )

9. ABCD is a square, VO is the altitude of the pyramid. Find the projection of VB on ABCD. BBD CBC AOB DAB 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. What is the foot of perpendicular from V to the plane ABCD? Back

11. 3. Correct ！ Next The projection of VB on the plane ABCD is OB. (Click and right-button drag the figure to change the view angle. )

12. BBM CCM AAM DOM 4. (Hold down the right mouse button and drag to change the view angle.) ABCD is a square, M is the mid-point of BC, and VO is the altitude of the pyramid. Find the projection of VM on the plane ABCD.

13. 4. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from V to the plane ABCD? Back

14. 4. Correct ！ Next The projection of VM on the plane ABCD is OM. (Click and right-button drag the figure to change the view angle. )

15. OABC is a triangular pyramid,  AOB = 90  and CO is the altitude. Find the projection of AC on the plane OAB. BOA COB AAB DOC 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. What is the foot of perpendicular from C to the plane OAB? Back

17. 5. Correct ！ Next The projection of AC on the plane OAB is OA. (Click and right- button drag the figure to change the view angle. )

18. BPA CPB AOP DOC 6. (Hold down the right mouse button and drag to change the view angle.) OABC is a triangular pyramid,  AOB = 90  and CO is the altitude. P is a point on AB. Find the projection of AC on the plane OAB.

19. 6. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from C to the plane OAB? Back

20. 6. Correct ！ Next The projection of CP on the plane OAB is OP. (Click and right- button drag the figure to change the view angle. )

21. BOA COB AAB DOC 7. (Hold down the right mouse button and drag to change the view angle.) OABC is a triangular pyramid,  AOB = 90  and CO is the altitude. Find the projection of AC on the plane OBC.

22. 7. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from A to the plane OBC? Back

23. 7. Correct ！ Next The projection of AC on the plane OBC is OC. (Click and right- button drag the figure to change the view angle. )

24. ABCDEF is a triangular prism, in which ABCD and CDEF are rectangles,  BCF = 90 . Find the projection of AE on the plane ABCD. BAB CDE AAD DCD 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. What is the foot of perpendicular from E to the plane ABCD? Back

26. 8. Correct ！ Next The projection of AE on the plane ABCD is AD. (Click and right-button drag the figure to change the view angle. )

27. BAB CDE AAD DCD 9. (Hold down the right mouse button and drag to change the view angle.) ABCDEF is a triangular prism, in which ABCD and CDEF are rectangles,  BCF = 90 . Find the projection of AE on the plane CDEF.

28. 9. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from A to the plane CDEF? Back

29. 9. Correct ！ Next The projection of AE on the plane CDEF is AC. (Click and right-button drag the figure to change the view angle. )

30. BAC CBF AAB DFC 10. (Hold down the right mouse button and drag to change the view angle.) ABCDEF is a triangular prism, in which ABCD and CDEF are rectangles,  BCF = 90 . Find the projection of AF on the plane ABCD.

31. 10. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from F to the plane ABCD? Back

32. 10. Correct ！ Next The projection of AF on the plane ABCD is AC. (Click and right-button drag the figure to change the view angle. )

33. BDE CDF AEF DFC 11. (Hold down the right mouse button and drag to change the view angle.) ABCDEF is a triangular prism, in which ABCD and CDEF are rectangles,  BCF = 90 . Find the projection of AF on the plane CDEF.

34. 11. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from A to the plane CDEF? Back

35. 11. Correct ！ Next The projection of AF on the plane CDEF is DF. (Click and right-button drag the figure to change the view angle. )

36. BAD CAE AEF DED 12. (Hold down the right mouse button and drag to change the view angle.) ABCDEF is a triangular prism, in which ABCD and CDEF are rectangles,  BCF = 90 . Find the projection of AF on the plane ADE.

37. 12. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from F to the plane ADE? Back

38. 12. Correct ！ Next The projection of AF on the plane ADE is AE. (Click and right- button drag the figure to change the view angle. )

39. VABCD is a rectangular pyramid, ABCD is a rectangle, and VD is the altitude. Find the projection of VC on the plane ABCD. BAC CCD AAB DVD 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. What is the foot of perpendicular from V to the plane ABCD? Back

41. 13. Correct ！ Next The projection of VC on the plane ABCD is CD. (Click and right-button drag the figure to change the view angle. )

42. BBC CBD AAB DVD 14. (Hold down the right mouse button and drag to change the view angle.) VABCD is a rectangular pyramid, ABCD is a rectangle, and VD is the altitude. Find the projection of VB on the plane ABCD.

43. 14. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from V to the plane ABCD? Back

44. 14. Correct ！ Next The projection of VB on the plane ABCD is BD. (Click and right-button drag the figure to change the view angle. )

45. BVB CVD AVA DCD 15. (Hold down the right mouse button and drag to change the view angle.) VABCD is a rectangular pyramid, ABCD is a rectangle, and VD is the altitude. Find the projection of VC on the plane VAD.

46. 15. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from C to the plane VAD? Back

47. 15. Correct ！ Next The projection of VC on the plane VAD is VD. (Click and right- button drag the figure to change the view angle. )

48. BVC CVD AVA DBD 16. (Hold down the right mouse button and drag to change the view angle.) VABCD is a rectangular pyramid, ABCD is a rectangle, and VD is the altitude. Find the projection of VB on the plane VAD.

49. 16. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from B to the plane VAD? Back

50. 16. Correct ！ Next The projection of VB on the plane VAD is VA. (Click and right- button drag the figure to change the view angle. )

51. BVC CVD AVA DCD 17. (Hold down the right mouse button and drag to change the view angle.) VABCD is a rectangular pyramid, ABCD is a rectangle, and VD is the altitude. Find the projection of VB on the plane VCD.

52. 17. Incorrect! Hint: Click and right-button drag the figure to change the view angle. What is the foot of perpendicular from B to the plane VCD? Back

53. 17. Correct ！ EndRestart The projection of VB on the plane VCD is VC. (Click and right- button drag the figure to change the view angle. )