已知弧度数为2的圆心角A所对的弦长为L=4,则这个圆心角所对的弧长为C?
弧半径为R.
A=2弧度=2*180/PI=114.5916度
R=(L/2)/SIN(A/2)
=(4/2)/SIN(114.5916/2)
=2/SIN(57.2958)
=2.377
C=A*R=2*2.377=4.754