Convert from degrees to radians. For parts (a) - (d), give exact answers. For part (e), approximate using your calculator, and round your answer to four decimal places:
(a) $60^\circ$ =
(b) $315^\circ$=
(c) $-30^\circ$ =
(d) $20^\circ$ =
(e) $2 \pi^\circ$ =

Hint: