弧长C=11.8 弦高H=0.8 求弦长L
弧半径为R,圆心角为A.
Rn+1=(1-(Rn*COS(C/(2*Rn))-Rn+H)/((C/2)*SIN(C/(2*Rn))-H))*Rn
R0=20
R1=21.397
R2=21.617
R3=21.622
R4=21.622
弧半径R=21.622
A=C/R
=11.2/21.622
=0.518弧度
=0.518*180/PI
=29.68度
L=2*R*SIN(A/2)
=2*21.622*SIN(29.68/2)
=11.08