已知半径R=3000mm 铉长L=4800mm 求弧长C?
弧所对的圆心角为A.
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((4800/2)/3000)
=106.26度
=106.26*PI/180
=1.85459弧度
C=R*A=3000*1.85459=5563.77mm