弦长L=4.3米 弧高H=1.05米,怎样计算弧长C?弧半径为R,圆心角为A.R^2=(R-H)^2+(L/2)^2R^2=R^2-2*R*H+H^2+L^2/42*R*H=H^2+L^2/4R=H/2+L^2/(8*H)=1.05/2+4.3^2/(8*1.05)=2.726米A=2*ARC SIN((L/2)/R)=2*ARC SIN((4.3/2)/...