圆弧的弦长L=4.4米 弧高H=0.4米求弧长C?
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*H*R+H^2+L^2/4
2*H*R=H^2+L^2/4
R=H/2+L^2/(8*H)
=0.4/2+4.4^2/(8*0.4)
=6.25米
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((4.4/2)/6.25)
=41.219度
=41.219*PI/180
=0.719414弧度
C=R*A=6.25*0.719414=4.496米