Pythagorean Theorem Calculator

Find the missing side of a right triangle using the Pythagorean theorem. Calculate area, perimeter, and angles.

Solve For

Side A

Side B

Tab to move between fields

Result

Hypotenuse5

Triangle Area6

Perimeter12

Angle A36.87°

Angle B53.13°

How to Use This Calculator

Choose the mode: find the hypotenuse (c) from legs a and b, or find a missing leg from the hypotenuse and one leg.
The Pythagorean theorem states: a² + b² = c², where c is always the hypotenuse (the longest side, opposite the right angle).
Enter the two known sides; the third is derived by solving the equation algebraically.
The calculator also reports the triangle's area (½ × a × b) and perimeter (a + b + c).
Angles A and B (opposite sides a and b) are found using inverse trig: angle A = arctan(a/b).
All side lengths must be positive; the hypotenuse must be longer than either leg.

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