Question

How to quickly convert degrees to radians?

Answer 1

180 degrees is the same as $\pi$
So if you have to convert 60 degrees to radians, do it like this:
$60* \frac{ \pi }{180}$
Then you reduce between the 60 and the 180.  60 goes into itself once and into 180 3 times, so 60 degrees is the same as $\frac{ \pi }{3}$