扇形的半径:(AB/2)/sin(1弧度/2)=1/sin28.65=1/0.48≈2.1
扇形的面积S=r^2θ/2=2.1*1/2≈2.1
弧长=rθ≈2.1
扇形的周长=弧长+2r≈2.1+4.2≈6.3