📐 Right Triangle Calculator
Solve right triangles from sides or angles
Enter any 2 of 3 sides (leave one empty)
How Right Triangle Solving Works
Formula
a² + b² = c² (Pythagorean theorem)
- 1Enter any two known values: two sides, or one side plus one acute angle.
- 2If two sides are known, the third is found using the Pythagorean theorem.
- 3If a side and angle are known, trigonometric ratios (sin, cos, tan) find the rest.
- 4All three angles are calculated (one is always 90°).
- 5Perimeter and area are computed from the complete triangle.
About Right Triangle Calculator
Solve any right triangle. Enter two sides or one side and one angle to find all missing sides, angles, perimeter, and area. Shows trigonometric relationships.
Frequently Asked Questions
What is the Pythagorean theorem?
It states that in a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: a² + b² = c².
Which side is the hypotenuse?
The hypotenuse is the longest side, opposite the 90° angle. It is always larger than either of the other two sides.
What are sine, cosine, and tangent?
For an acute angle in a right triangle: sin = opposite/hypotenuse, cos = adjacent/hypotenuse, tan = opposite/adjacent. These ratios let you find unknown sides from angles.