Pythagorean Theorem Calculator
Hypotenuse c
5
numeric ≈ 5
Step-by-step solution
- 1
The Pythagorean theorem
In a right triangle, the square of the hypotenuse equals the sum of the squares of the two legs.
- 2
Substitute the known sides
Substitute the legs a = 3 and b = 4 into the theorem.
- 3
Compute exactly
Square each leg and add: 9 + 16 = 25. Fraction arithmetic keeps this exact.
- 4
Take the square root
Take the square root of both sides: c = √25.
- 5
Simplify the radical
The value under the root, 25, is a perfect square, so the answer is exactly 5, with no radical left.
- 6
Result
With legs a = 3 and b = 4, the hypotenuse is c = 5 ≈ 5.
About the Pythagorean theorem
In any right triangle, the square on the hypotenuse equals the sum of the squares on the two legs: a² + b² = c². It is the foundation of distance measurement in geometry.
The converse classifies any triangle: if the sum of the two shorter squares equals the longest square it is right-angled, if the sum is greater it is acute, and if it falls short it is obtuse.
Whole-number solutions like 3-4-5 or 5-12-13 are Pythagorean triples; when the answer is not whole, this calculator keeps it exact as a simplified radical (√50 = 5√2) instead of a rounded decimal.