Math Animations on Instagram: "The Pythagorean theorem is a fundamental theorem in geometry that establishes a relationship between the side lengths of a right triangle. It states that in a right triangle, the sum of the squares of the lengths of the two shorter sides is equal to the square of the length of the longest side, called the hypotenuse. This theorem is named after the Greek mathematician Pythagoras, who lived in the 6th century BC and is considered one of the founders of mathematics.