The earliest recorded pythagorean theorem in ancient China is

Chapter nine arithmetic. Pythagorean theorem is a basic geometric theorem, which means that the sum of the squares of two right angles of a right triangle is equal to the square of the hypotenuse. In ancient China, the right triangle was called Pythagorean, which was first put forward by Zhao Shuang in his book Parallel Computing. The first ancient masterpiece that systematically recorded and explained Pythagorean theorem was Nine Chapters Arithmetic. Nine Chapters Arithmetic is a mathematical monograph written by Zhang Cang and Geng Shouchang in ancient China, which contains 246 mathematical problems.