The Pythagorean theorem is a fundamental geometric relationship that applies to right triangles. It states that the sum of the squares of the two shorter sides (legs) of a right triangle is equal to the square of the longest side (hypotenuse). The formula is: a² + b² = c².
Enter any two sides of a right-angled triangle to calculate the third using the Pythagorean theorem:
Formula
c² = a² + b² (where c is the hypotenuse)
a² = c² – b² or b² = c² – a² (for solving a leg)
Example
If side a = 3 and side b = 4, then:
c² = 3² + 4² = 9 + 16 = 25 → c = √25 = 5