Pythagorean theorem is a special case of cosine theorem. This theorem is also called "quotient height theorem" at home and "Pythagoras theorem" or "hundred cows theorem" abroad. (After Pythagoras discovered this theorem, he beheaded a hundred cows to celebrate, so it was also called the "hundred cows theorem"), and the French and Belgians also called this theorem the "donkey bridge theorem". They discovered Pythagorean theorem later than our country, and they were the first country to discover this geometric treasure. ?

At present, the proof method of learning textbooks for junior two students is Zhao Shuangxian's map, which proves to be Zhu Qing's access map. ?

Pythagorean theorem is a basic geometric theorem, it is one of the most important tools to solve geometric problems with algebraic ideas, and it is one of the ties that combine numbers and shapes. ?

The sum of squares of two right angles of a right triangle is equal to the square of the hypotenuse. If a, b and c are used to represent the right side and hypotenuse of a right triangle, then A 2+B 2 = C 2.

Pythagorean theorem states that

The sum of squares of two right-angled sides of a right-angled triangle (short hook and long strand) is equal to the square of the side length of the hypotenuse (chord). ?

That is to say, if the right sides of a right triangle are A and B and the hypotenuse is C, then the square of A+the square of B = the square of C A 2 +b 2 =c 2? Pythagorean theorem has found about 500 proofs, which is one of the theorems with the most proofs in mathematics. ? Shang Gao, a famous mathematician in ancient China, said: "If you tick three and divide into four, you will string five." It is recorded in Nine Chapters of Arithmetic.