1. Animations from Cabri 3D 1. Planes of symmetry of a cube Adrian Oldknow November 2004

2. A new Cabri 3D page

3. Create a ray

4. and a point on the ray

5. Use point symmetry

6. Rotate for a 3 rd point

7. Reflect for the 4 th point

8. Draw a parallel

9. Construct a perpendicular

10. Find the intersection point

11. Point symmetry again

12. and some reflections

13. Draw a perpendicular

14. Draw a circle around an axis

15. Find the intersections

16. Create a parallel plane

17. Create another perpendicular

18. and find the intersection

19. Start tidying up!

20. Another perpendicular

21. Point symmetry for the others

22. Hide some constructions

23. Until all you see are points!

24. Now join up some dots

25. And reflect in the mid-plane

26. The cube is nearly there

27. At last – a cube!

28. Hide the spare dots

29. Colour the edges

30. Label the vertices

31. Spin it a bit

32. Define a polygon

33. Is it in a plane of symmetry?

34. Here’s one diagonal

35. Is the other diagonal equal?

36. How many diagonals like this?

37. And like this?

38. Did you get all these?

39. How many planes like this?

40. And like this?

41. Here are 2 joining green edges

42. And the third: the edge bisector

43. So how many planes of symmetry does a cube have?

44. Dots at the centres of each face

45. What shape do they make?

46. Looks familiar?

47. Well, that’s another story!