Home of Calculators Logo

Pythagorean Theorem Calculator

Pythagorean Theorem Calculator

Solve right triangles by finding sides, perimeter, area, and angles

MATH
Hypotenuse (c)
5.0000
Perimeter
12.0000
Area
6.0000
Angle α (Opposite a)
36.9°
Angle β (Opposite b)
53.1°

Triangular Dimension Visual (scaled)

a=3.0b=4.0c=5.090°

Step-by-Step Solver

[1]c² = a² + b²
[2]c² = 3² + 4²
[3]c² = 9 + 16
[4]c² = 25
[5]c = √25 = 5.0000
Find the missing side of a right triangle using a² + b² = c².

Evidence-based guide

Pythagorean Theorem and Right Triangle Calculations

The Pythagorean Theorem is a fundamental principle in geometry stating that in a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.

Formula and calculation methods

c² = a² + b²

Finding the Hypotenuse (c)

Given two legs (a and b), calculate the hypotenuse: c = √(a² + b²).

Finding a Leg (a or b)

Given the hypotenuse (c) and one leg (a), calculate the other leg: b = √(c² − a²).

How to interpret your result

In addition to side lengths, the solver computes the area, perimeter, and all interior angles of the right triangle (which sum to 180 degrees).

Limitations and safety

The theorem applies strictly to Euclidean flat-plane geometry and right-angled triangles (where one angle is exactly 90 degrees).

Frequently asked questions

What is a Pythagorean triple?

A Pythagorean triple consists of three positive integers (a, b, c) that satisfy the equation a² + b² = c² (e.g. 3, 4, 5 or 5, 12, 13).

How are angles calculated in the triangle?

We use inverse trigonometric functions: α = arcsin(a/c) and β = arcsin(b/c).

Can the leg be longer than the hypotenuse?

No. The hypotenuse is always the longest side of a right triangle. If a leg is entered as greater than or equal to the hypotenuse, a validation error is thrown.