A Pythagorean triple, also called a triplet, are any three numbers that go together to validly fulfill the Pythagorean theorem, a2 + b2 = c2. The Pythagorean theorem states that for any right angle triangle, the sum of the two shortest sides squared will be equal to the length of the hypotenuse, or longest side, squared.
There are an infinite amount of Pythagorean triples, although the smaller ones are much more common. The first three sets of Pythagorean triples are (3, 4, 5), (5, 12, 13) and (7, 24, 25). To verify that a set is a valid triple, square all of the numbers and add the two smallest terms together. For example, 3 and 4 squared are 9 and 16 respectively, added together equals 25, which is 5 squared.