从左到右有三个扇形;
L(AA1)=R1θ1=2(π/2)=π
L(A1A2)=R2θ2=1(π/2)=π/2
L(A2A3)=R3θ3=√3(π/3)
L(全)=π+(π/2)+(√3/3)π=[(3/2)+(√3/3)]π
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扇形面积是:(1/2)LR
S(全)=S1+S2+S3=(1/2)π*2+(1/2)(π/2)*1+(1/2)(√3/3π)*√3
=π+π/4+π/2
=7π/4