Pythagoras' most outstanding achievement in mathematics is that he discovered Pythagoras' theorem. Pythagoras found that there seems to be a special relationship between the three sides of a right triangle on a tile. So, it first writes an A on one right-angled side, a B on the other right-angled side and a C on the hypotenuse, and uses A, B and C to represent the lengths of the three sides of the triangle respectively. Two adjacent black triangles form a square with an area of a = a, and the other two adjacent black triangles form a square with an area of b = b. Four adjacent black-and-white triangles are combined into a larger square with an area of c = c, and its area is equal to the sum of the areas of two small squares. From this, he obtained the relationship between the three sides of a right triangle: the square of a+the square of b = the square of c.