see explanation

##color(blue)( to convert radians to degrees)##

( angle in radians) ## xx 180/pi ##

example: convert ## pi/2 color(black)( radians to degrees )##

angle in degrees ##= cancel(pi)/2 xx 180/cancel(pi) =180/2 = 90^@##

##color(red)( to convert degrees to radians) ##

(angle in degrees)## xx pi/180 ##

example : convert 90 to radians

angle in radians = ##cancel (90) xx pi/cancel(180) =pi/2 ##