已经知道弓形的弦长为L=4.24米弦中心到弧中心的距离的H=0.55米求弧长C?弧半径为R,弧所对的圆心角为A.R^2=(R-H)^2+(L/2)^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)=0.55/2+4.24^2/(8*0.55)=4.361A=2*A...