扇形面积是1平方米，周长为4米，则扇形中心角的弧度数是（）A.2B.1C.πD.π2

Question

(π)/(2)(π)/(2)ππ22

Answer 1

设扇形的圆心角的弧度数为α，圆的半径为r，则

2r+αr＝4

(1)/(2)αr2＝1

解得：α=2
故选：A．

2r+αr＝4

(1)/(2)αr2＝1

2r+αr＝4

(1)/(2)αr2＝1

2r+αr＝4

(1)/(2)αr2＝1

2r+αr＝4

(1)/(2)αr2＝1

2r+αr＝42r+αr＝42r+αr＝4(1)/(2)αr2＝1(1)/(2)αr2＝1(1)/(2)111222αr2＝12＝1
解得：α=2
故选：A．