Pythagorean theorem or Pythagorean theorem is also called Pythagorean theorem. Is a basic geometric theorem, which is traditionally proved by Pythagoras in ancient Greece. It is said that after Pythagoras proved this theorem, he beheaded a hundred cows to celebrate, so it is also called "Hundred Cows Theorem". In China, Zhou Kuai Shu Jing recorded a special case of Pythagorean Theorem, which was reportedly discovered by Shang Dynasty's Shang Dynasty, so it is also called Shang Gao Theorem. Zhao Shuang in the Three Kingdoms period made detailed comments on Pythagorean Theorem as proof in Zhou Bi suan Jing. France and Belgium are called donkey bridge theorem, and Egypt is called Egyptian triangle.

The famous Pythagorean theorem was first put forward by Shang Gao, a mathematician in the Western Zhou Dynasty.

As early as BC 1 1 in the early Western Zhou Dynasty, the mathematician Shang Gao once talked with the assistant Duke Zhou about the property of a right-angled triangle. If its two right-angled sides are 3 and 4 respectively, the hypotenuse is 5. Using the method of quotient height, it is easy to get a more general conclusion: in a right triangle, the sum of the squares of two right-angled sides is equal to the square of the hypotenuse. This is Pythagorean theorem or quotient height theorem, which is called Pythagorean theorem in the west.

Pythagorean theorem is an ancient and widely used theorem. For example, starting from Pythagorean theorem, square roots and square roots are gradually developed; Finding pi by pythagorean theorem. It is said that more than 4000 years ago, Dayu in China used Pythagorean Theorem to measure the topographic differences between the two places in the process of water control. Pythagorean theorem, with its concise and beautiful form and rich and profound content, fully embodies the harmonious relationship of nature. People have always been enthusiastic about Pythagorean theorem. There are dozens of proofs of the theorem alone, and even the famous great physicist Einstein gave a proof. Hua, a famous mathematician in China, once talked about how to talk with "aliens". He suggested that a graphic shape diagram reflecting Pythagorean theorem should be used as the language for talking with "aliens". This fully shows that Pythagorean theorem is one of the most essential and basic laws in nature, and China people are ahead in discovering and applying such an important law.