1. Form 1 Mathematics Chapter 9

2. Lesson requirement Textbook 1B Workbook 1B Notebook Folder Before lessons start Desks in good order! No rubbish around! No toilets!

3. Reflectional Symmetry ( 反射對稱 ) Rotational Symmetry ( 旋轉對稱 )

4. 1 axis of symmetry

5. 4 axes of symmetry

7. 6 axes of symmetry

9. 2-fold rotational symmetry Centre Of Rotation

10. Centre Of Rotation 3-fold rotational symmetry

11. 5-fold rotational symmetry Centre Of Rotation

12. 4-fold rotational symmetry Centre Of Rotation

13. 5-fold rotational symmetry Centre Of Rotation

14. 3-fold 5-fold4-fold

15. Pages 84 – 85 of Textbook 1B Questions 2 – 10 Pages 38 – 39 of Workbook 1B Questions 3 – 9

16. Four types of transformations: 1. Translation 2. Reflection 3. Rotation 4. Enlargement / reduction Let’s look at this now

17. It translates the figure to the left by 1 unit.

19. A B C A’ B’C’

20. A B C C Arrow A is translated 4 units to the right and 2 units downwards to give Arrow C.

21. Four types of transformations: 1. Translation 2. Reflection 3. Rotation 4. Enlargement / reduction Let’s look at this now

23. It reflects the figure about the line of reflection AB. A B

24. A B C D E A’ B’ F’ D’ E’ X Y F G C’ G’

26. Figure A Figure B Line of reflection What’s this line called?

27. Four types of transformations: 1. Translation 2. Reflection 3. Rotation 4. Enlargement / reduction Let’s look at this now

28. Centre of rotation

29. It rotates the figure anti-clockwise around point G by 90 o. G What is point G called?

30. A B C D E A’ B’ F’ D’ E’ X Y F G C’ G’

31. A’ A B C D E ╳O╳O E’ D’C’ B’ The arrow ABCDE is rotated clockwise by 90° about the point O to obtain image A’B’C’D’E’

32. A B C ╳O╳O A’ B’ C’ C’’ B’’ A’’ C’’’ B’’’ A’’’

33. Four types of transformations: 1. Translation 2. Reflection 3. Rotation 4. Enlargement / reduction Let’s look at this now

34. The robot enlarges the figure to 2 units long and 2 units high The robot ??? the figure to ?? units ???? and ?? units ???? Another way: The robot ENLARGES the figure by 2 TIMES

35. The robot enlarges the figure by 2 times This is called ENLARGEMENT.

36. A B C A’B’

37. The robot reduces the figure to 1 unit long and 1 unit high The robot ??? the figure to ?? units ???? and ?? units ???? Another way: The robot REDUCES the figure by ONE HALF

38. The robot reduces the figure by one half This is called REDUCTION.

39. A B C A’B’

41. ╳O╳O

42. Pages 100 – 101 of Textbook 1B Questions 1 – 14 Pages 40 – 41 of Workbook 1B Questions 1 – 2

43. Missing Homework, Re-do Homework Today! SHW (I) and SHW (II) 11 Mar (Mon) External Review 13 Mar (Wed) Open Book Quiz 13 Mar (Wed) Close Book Quiz 15 Mar (Fri) – To be confirmed

44. Enjoy the world of Mathematics! Ronald HUI