已知半径R=5.6和弦长L=7.2 求弧长C?
弧所对的圆心角为A.
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((7.2/2)/5.6)
=80.01度
C=π*R*A/180=π*5.6*80.01/180=7.82