海島算經 by active 3rd century-4th century Hui Liu

"海島算經" by Liu Hui is a mathematical manual written during the Three Kingdoms era (220–280). Originally an extension of "The Nine Chapters on the Mathematical Art," it became a separate work during the Tang dynasty and was included in imperial mathematics examinations. The text presents practical surveying problems, demonstrating how to measure inaccessible distances and heights using poles and geometric principles. Nine problems cover scenarios like determining island heights, mountain elevations, and city dimensions through ingenious indirect measurement techniques. ... Read more