Basically the radian thing is easy, as I know it.
The pi symbol denotes 180 degrees.
If you want to convert something in terms of pi, eg 30 degrees, then you do 30 / 180 = 1 / 6 and then you times it by pi,
so it is pi / 6.
Eg convert 60 to radian.
That would be 60 / 180 = 1 / 3 = pi / 3...