Incircle's Radius of Right-Angled Triangle by LIU Hui (劉徽)
LIU Hui's (劉徽 circa 3rd century) method of finding the radius of a right-angled triangle in his commentary on Problem 16 in Chapter 9 of the ancient Chinese mathematical treatise Jiu Zhang Suan Shu (九章算術 The Nine Chapters on the Mathematical Art).
