知道拱高H=1110 弦长L=2740 求弧长C和半径R怎么算啊?设A为弧所对的圆心角.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)=1110/2+2740^2/(8*1110)=1400.45A=2*ARC SIN((L/2)/R)=2...