A=2弧度=2*180/PI=114.592度R=(2/2)/SIN(A/2) =1/SIN(57.296) =1.188这个圆心角所夹扇形面积=PI*1.188^2*114.592/360 =1.142
R=(2/2)/SIN(A/2) =1/SIN(57.296) =1.188这个圆心角所夹扇形面积=Pi*1.188^2*114.592/360 =1.142