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 also one of the ties of the combination of numbers and shapes.
Inverse Theorem of Pythagorean Theorem: If the lengths of three sides of triangle A, B and C satisfy a? +b？ =c？ Then this triangle is a right triangle, where c is the hypotenuse. That is to say, the sum of squares of the lengths of two right angles of a right triangle is equal to the square of the length of the hypotenuse.
The number of Pythagoras:
1. Positive integers with three sides of three right triangles are called pythagorean numbers, that is, when a, b and c are positive integers, a, b and c are called the set of pythagorean numbers.
2. Remember that common Pythagorean numbers can improve the speed of solving problems, such as 3, 4 and 5; 6、8、 10; 5、 12、 13; 7, 24, 25, etc.
3. N groups of pythagorean numbers are represented by algebraic expressions with letters: (n is a positive integer); (n is a positive integer); (m>n, m and n are positive integers).