[填空题]
Express the followin3g(u :yo1gj- 4tcftg pg angles in radians: e o 65u*8, vwu3ofkuhpcbva *,(a) 30 $^{\circ} $, (b) 57 $^{\circ} $, (c) 90 $^{\circ} $, (d) 360 $^{\circ} $, and (e) 420 $^{\circ} $. Give as numerical values and as fractions of $\pi$.(Round to two decimal places) (a) $rad$ (b) $rad$ (c) $rad$ (d) $rad$ (e) $rad$