已知弦长L=6.3米,拱高H=1米,求半径R和弧长C?
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+6.3^2/(8*1)
=5.461米
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((6.3/2)/5.461)
=70.45度
=70.45*PI/180
=1.22959弧度
C=A*R
=1.22959*5.461
=6.715米