弦长是L=10.84米,弦高是H=2.1米,求弦所对应的弧长C?弧的半径为R,弧所对的圆心角为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)=2.1/2+10.84^2/(8*2.1)=8.044米A=2*ARC SIN((L/2)/R)...