**The Pythagorean theorem forms the basis of trigonometry and, when applied to arithmetic, it connects the fields of algebra and geometry, according to Mathematica.ludibunda.ch.** It has been applied to real-world problems since at least 1500 B.C., when it was used by the ancient Babylonians to accurately lay foundations for buildings, says University of Kentucky. Today, its practical applications are more diverse than ever.

From the University's Mathematical Sciences Department, "the Pythagorean theorem states that the square on the hypotenuse of a right triangle has an area equal to the combined areas of the squares on the other two sides." The converse of this is true as well.

Though its use goes back much further in history, the credit for proving the Pythagorean theorem goes to the philosopher and mathematician Pythagoras of Samos, who worked on it sometime between 580-500 B.C.

The uses of this theorem are almost limitless. Professor David Joyce of Clark University states that some practical uses of trigonometry are astronomy, geography, physics and engineering. Betterexplained.com shows us how the theorem can be expanded beyond triangles and geometry to apply to any shape and "any formula that squares a number." Because of this, it can be applied to some very unexpected fields, such as computer science and people in a social network.