假设半径为R ,
R^2 = (弦长/2)^2 + (R - 弦中心到弧顶)^2
代入数值：R^2 = (3910/2)^2 + (R - 550)^2
得 1100R= 1955^2 + 550^2 = 4124525
R =4124525 / 1100 = 3749.56818181818
圆心角 = 2 arcsin(弦长/2/R) = 62.8515 °
弧长 = R×圆心角/180 *π ＝ 4113.1
弧长如何计算已知弦长3910,弦中心到弧顶550.弧长是多少?半径是多少?圆心角是多少?