Rules of Transposition

Do you know that we have simple rules to transpose minus (-ve negative) cylinder form to plus (+ve positive) cylinder form and vice versa? Just follow these rules below, InsyaAllah, you will always obtain a correct answer.

Rules of transposition

1.Add the sph and cyl, taking into account their sign

2.Change their sign of the cyl

3.Alter the axis by 90°

  a. if the original axis is 90° or less, add 90° to it

  b. if the original axis is over 90°, subtract 90° from it

  

Now, you've understand the rules right? Let's try these questions below;

1. +4.00/-2.00 x 180 
2. -400/-2.00 x 175 
3. +5.00/+3.00 @ 120 
4. -11.00/-11.00 @ 65 
5. -0.75/-0.25 x 42 
6. +4.25/-1.25 x20 
7. -6.75/-2.75 x 80 
8. -22.00/-1.25 x174 
9. -12.00/+5.00 x 155
10. +7.50/-2.00 x 25
11. -4.00/-2.00 x 180 
12. +400/-2.00 x 175 
13. +5.00/-3.00 @ 120 
14. pl/-11.00 @ 65 
15. -1.75/-0.25 x 42 
16. +5.25/-1.25 x20 
17. -6.25/-2.75 x 80 
18. -22.00/-11.25 x174 
19. -12.00/-5.00 x 55
20. +7.50/-2.00 x 125
21. -11.00/+5.00 x 35
22. +6.00/-2.50 x 105
23. +5.00/-2.00 x 180 
24. -4.00/-3.00 x 175 
25. +5.00/-3.00 @ 120 
26. -11.00/-1.25 @ 65 
27. +0.75/-0.25 x 42 
28. -5.25/-1.25 x20 
29. -6.75/-2.75 x 180 
30. -22.00/-1.25 x72
31. -12.00/+5.00 x 5
32. +7.50/-4.00 x10
33. -4.00/-1.00 x 80 
34. +400/-2.00 @ 90
35. +5.00/-2.00 @ 120 
36. pl/-1.00 @ 165 
37. -1.75/-0.25 @ 42 
38. +5.25/-1.00 x120 
39. -6.25/-2.75 x@80 
40. -20.00/-1.00 x174 
41. -11.00/-4.00 x 55
42. +7.75/-3.00 x 125
43. -1.00/+5.00 x 35
44. +6.00/+2.50 x 115
45. -2.00/-7.00 @ 100

Please grab one question for each of you.. (Year 1 & Year 2) first come first serve basis, Year 3 & Year 4 are also encouraged to answer these questions.