弦长3500mm弧长3700mm求弦高?急////

弦长L=3500mm弧长C=3700mm求弦高H?
弧半径为R,弧所对的圆心角为A.
Rn+1=(1+(L-2*Rn*SIN(C/(2*Rn)))/(L-C*COS(C/(2*Rn))))*Rn
R0=3000
R1=3107.45
R2=3220.93
R3=3221.82
R4=3221.82
R=3221.82mm
A=C/R=3700/3221.82=1.148419弧度=1.148419*180/PI=65.8度
H=R-R*COS(A/2)=3221.82-3221.82*COS(65.8/2)=516.71mm