Pythagorean theorem, in our country, the property that the sum of squares of two right angles of a right triangle is equal to the square of the hypotenuse is called Pythagorean theorem or Pythagorean theorem. Is a basic geometric theorem, which is traditionally considered to be 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. In ancient China, the shorter right angle side of a right triangle was called a hook, the longer right angle side was called a chord, and the hypotenuse was called a chord.

Theorem:

If the two right angles of a right triangle are A and B and the hypotenuse is C, then A? +b？ =c？ That is to say, the sum of squares of two right angles of a right triangle is equal to the square of the hypotenuse.

If three sides a, b and c of a triangle satisfy a? +b？ =c？ Then this triangle is a right triangle. (called the inverse theorem of Pythagorean theorem)