Pythagorean Theorem
Calculate sides of a right triangle: a² + b² = c²
Right Triangle Calculator
Find c (hypotenuse)
Find a (leg)
Find b (leg)
3² + 4² = 5² → 9 + 16 = 25 ✓
Common Pythagorean Triples
Integer solutions where a² + b² = c²
3, 4, 5
5, 12, 13
8, 15, 17
7, 24, 25
20, 21, 29
9, 40, 41
About the Theorem
The Formula
In a right triangle, the square of the hypotenuse (the side opposite the right angle) equals the sum of the squares of the other two sides: a² + b² = c²
Finding the Hypotenuse
c = √(a² + b²). The hypotenuse is always the longest side and is opposite the 90° angle.
Finding a Leg
a = √(c² – b²) or b = √(c² – a²). Subtract the square of the known leg from the square of the hypotenuse.