看圖來計算... 兩圓直徑皆為5上下圓相交0.52.5*2.5*3.14/2=9.8125兩圓交集那那圓 直徑 1 半徑0.50.5*0.5*3.14/2=0.39259.8125-0.3925 = 9.42