If one finds it hard to remember the above angles and factors, remember the 6th sense;
10 deg - 1/6
20 deg - 2/6
30 deg - 3/6
40 deg - 4/6
50 deg - 5/6
60 deg (or more) - 6/6
It is the exact same as the above but I find it more instinctive and easier to remember.
Regards,
DFC