弧长C=198 弦长L=147求圆半径R?
Rn+1=(1+(L-2*Rn*SIN(C/(2*Rn)))/(L-C*COS(C/(2*Rn))))*Rn
R0=80
R1=75.918
R2=76.346
R3=76.352
R4=76.352
圆半径R=76.352