已知弧的弦长为L=10M,高为H=O.5M.求直径D和弧长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)=0.5/2+10^2/(8*0.5)=25.25米D=2*R=2*25.25=50.5米A=2*ARC...