已知拱高弦长求弧长我有4个尺寸帮我求弧长,在知道里面看到公式由于文化底看不懂,请帮我直接算结果.弦长2404拱高664弦
1个回答
已知拱高H=664弦长L=2404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)
=664/2+2404^2/(8*664)
=1419.95
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((2404/2)/1419.95)
=115.667度
C=PI*R*A/180=PI*1419.95*115.667/180=2866.57
已知拱高H=669弦长L=1340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)
=669/2+1340^2/(8*669)
=670
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((1340/2)/670)
=179.83度
C=PI*R*A/180=PI*670*179.83/180=2102.87
