扇形的半径是30厘米,圆心角是45度,求它的周长,面积?
扇形的半径R=30cm
圆心角A=45度=45*PI/180=0.25*PI弧度
扇形的周长=R*A+2*R
=30*0.25*PI+2*30
=23.56+60
=83.56cm
扇形的面积=PI*R^2*A/360
=PI*900*45/360
=353.43cm^2