知道弦长和拱高求弧长,弦长是L=3.28m拱高是H=0.6m,求弧长C多少m?
弧半径为R,弧所对的圆心角为A.
R^2=(R-H)^2+(L/2)^2
R^2=R^2-2*R*H+H^2+L^2/4
2*R*H=H^2+L^2/4
R=H/2+L^2/(8*H)
=0.6/2+3.28^2/(8*0.6)
=2.5413m
A=2*ARC sin((L/2)/R)
=2*ARC sin((3.28/2)/2.5413)
=80.38度
=80.38*PI/180
=1.40291弧度
C=A*R=1.40291*2.5413=3.5653m