Standing pole shadow and string diagram

The Pythagorean theorem is a fundamental geometric theorem that states that the sum of the squares of the two right angled sides of a right angled triangle is equal to the square of the hypotenuse. In ancient China, a right angled triangle was called a Pythagorean shape, and the smaller side of the right angle was called a hook, while the longer side of the right angle was called the hypotenuse of the thigh and the hypotenuse was called a string. Therefore, this theorem is called the Pythagorean theorem, also known as the Shanggao theorem. There are currently about 500 proof methods for Pythagorean theorem, which is one of the theorems with the most proof methods in mathematics.

The unit is designed for unsupervised public use: controls are recessed or shielded, moving parts are enclosed, and the interface is operable by a child of about six with no instruction. Where a screen is used, the language can be switched without changing the hardware, and the content can be replaced on site.