已知内弦长及内弦高求弧长了,但不知道求外弧长怎么求?

已知内弦长L及内弦高H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)A=2*ARC SIN((L/2)/R)度=(2*ARC SIN((L/2)/R))*PI/180弧度C=R*A=R*((2*ARC SIN...