Here are the steps!
By using this formula;
Converting from Radians to Degrees
#"Radians" = pi/180^0 xx "Degrees"#
or
Converting from Degrees to Radians
#"Degrees" = 180^0/pi xx "Radians"#
So from your question..
Expressing #30^0# in Radians should be using this formula (Converting from Degrees to Radians)
#rArr 30^0# in Radians #-> "Degrees" = 180^0/pi xx "Radians"#
#color(white)(xxxxxxxiiixxxx)-> 30^0 = 180^0/(22/7) xx "Radians"#
#color(white)(xxxxxxxiiixxxx)-> 660/7 = 180/1 "Radians"#
#color(white)(xxxxxxxiiixxxx)-> 180 xx 7 color(white)(x)"Radians" = 660#
#color(white)(xxxxxxxiiixxxx)-> 1260color(white)(x)"Radians" = 660#
#color(white)(xxxxxxxiiixxxx)-> "Radians" = 660/1260#
#color(white)(xxxxxxxiiixxxx)-> "Radians" = 0.52 rad#