勾股定理,即直角三角形两直角边的平方和等于斜边的平方．我国是最早了解勾股定理的国家之一．我国古代称直角三角形为勾股形,并且把较短的直角边称为勾,较长的直角边称为股,斜边称为弦,所以称勾股定理,也有人称其为商高定理．勾股定理在西方被称为毕达哥拉斯定理．这条定理是几何学中一颗光彩夺目的明珠,应用十分广泛,被誉为“几何学的基石．” Pythagorean theorem, that is, the square sum of the right-angled triangles is equal to the square of the hypotenuse. China is one of the first countries to know the Pythagorean theorem. In ancient China, the right-angled triangle was called agouti-shaped, and the shorter right-angled edge was called a hook, the longer right-angled edge was called a strand, and the hypotenuse was called a string. Therefore, the Pythagorean Theorem was also called as the theorem of quotient height. The Pythagorean theorem is called Pythagorean theorem in the West. This theorem is a dazzling pearl in geometry. It is widely used and is known as “the cornerstone of geometry.”