半径为2cm，中心角为120°的扇形面积为（）A．π3cm2B．2π3cm2C．4π3cm2D．8π3cm2

Question

半径为2cm，中心角为120°的扇形面积为（　　）

A．(π)/(3)cm2
B．(2π)/(3)cm2
C．(4π)/(3)cm2
D．(8π)/(3)cm2

(π)/(3)cm2
B．(2π)/(3)cm2
C．(4π)/(3)cm2
D．(8π)/(3)cm2(π)/(3)ππ33m2
B．(2π)/(3)cm2
C．(4π)/(3)cm2
D．(8π)/(3)cm2m2
B．(2π)/(3)cm2
C．(4π)/(3)cm2
D．(8π)/(3)cm22
B．(2π)/(3)cm2
C．(4π)/(3)cm2
D．(8π)/(3)cm2
(2π)/(3)cm2
C．(4π)/(3)cm2
D．(8π)/(3)cm2(2π)/(3)2π2π33m2
C．(4π)/(3)cm2
D．(8π)/(3)cm2m2
C．(4π)/(3)cm2
D．(8π)/(3)cm22
C．(4π)/(3)cm2
D．(8π)/(3)cm2
(4π)/(3)cm2
D．(8π)/(3)cm2(4π)/(3)4π4π33m2
D．(8π)/(3)cm2m2
D．(8π)/(3)cm22
D．(8π)/(3)cm2
(8π)/(3)cm2(8π)/(3)8π 8π π π  33m2m22

Answer 1

扇形的圆心角的弧度数为(2π)/(3)，故扇形面积等于 (1)/(2)×(2π)/(3)×22=(4π)/(3) （cm² ），
故选C． (2π)/(3)2π2π2π333，故扇形面积等于 (1)/(2)×(2π)/(3)×22=(4π)/(3) （cm² ），
故选C． (1)/(2)111222×(2π)/(3)2π2π2π333×22=(4π)/(3) （cm² ），
故选C． 2=(4π)/(3) （cm² ），
故选C． (4π)/(3)4π4π4π333 （cm²2 ），
故选C．