如果A=1弧度的圆心角所对的弦长为L=2,那么该圆心角所对的弧长C为多少?
A=1弧度=1*180/PI=57.3度
L=2*R*SIN(A/2)
R=L/(2*SIN(A/2))=2/(2*SIN(1/2))=1/(SIN(0.5弧度))=1/(SIN(57.3/2))=1/(SIN(28.65度))