知弦长为L=6,拱高为H=1,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*R*H+H^2+L^2/4
2*R*H=H^2+L^2/4
R=H/2+L^2/(8*H)
=1/2+6^2/(8*1)
=5
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((6/2)/5)
=73.72度
=73.72*PI/180
=1.287002弧度
C=R*A=5*1.287002=6.435
知弦长为L=6,拱高为H=1,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*R*H+H^2+L^2/4
2*R*H=H^2+L^2/4
R=H/2+L^2/(8*H)
=1/2+6^2/(8*1)
=5
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((6/2)/5)
=73.72度
=73.72*PI/180
=1.287002弧度
C=R*A=5*1.287002=6.435