∵Rt△ABC中,∠C=90°,∠A=30°,AB=2,
∴BC=
AB=1 2
×2=1,AC=2×1 2
=
3
2
,
3
∴∠BAB′=150°,
∴S阴影=AB扫过的扇形面积-AC扫过的扇形面积=
-150×π×22
360
=150×π×(
)2
3
360
.5π 12
故答案为:
.5π 12
S阴影=S扇形BAB'+S△AB'C'-S扇形CAC'-S△ABC
易证△AB'C'≌△ABC
S阴影=S扇形BAB'-S扇形CAC'
△AB'C'≌△ABC
扇形BAB'与扇形CAC'对应的圆心角相等,均为150°
AB=2
AC=√3
S阴影=5/12*π*(4-3)=5/12*π