500 The li varied; it equated at one time to about one third of an English mile but has now been standardised to half a kilometre.
The following were influential in developing which subject in China: Liu Hui, Zu Geng, Li Chunfeng, Yang Hui, Shen Kuo, Liu Xin, Zhang Heng, Liu Hui, Zu Chongzhi and Wang Xiaotong?
