Right Triangle Calculator
Please provide 2 values below to calculate the other values of a right triangle. Calculate sides, angles, area, and perimeter instantly.
Supports degrees and radians. Perfect for trigonometry and geometry problems.
Enter any 2 values to calculate the rest
Sides
Angles (degree)
Why Use Our Right Triangle Calculator?
Flexible Inputs
Calculate using any two known values: two sides, or one side and one angle.
Precise & Fast
Get instant, accurate results for all sides, angles, area, and perimeter.
Educational
Learn about the relationships between sides and angles in a right triangle.
About Right Triangles
A right triangle is a type of triangle that has one angle measuring 90°. The side opposite the 90° angle is the longest side, known as the hypotenuse. The other two sides are called legs.
Pythagorean Theorem
For any right triangle with legs a and b and hypotenuse c:
a² + b² = c²This fundamental theorem allows you to find the length of any side if the other two are known.
Trigonometric Ratios
- Sine (sin α):
Opposite / Hypotenuse (a/c) - Cosine (cos α):
Adjacent / Hypotenuse (b/c) - Tangent (tan α):
Opposite / Adjacent (a/b)
Special Right Triangles
30°-60°-90° Triangle
Sides are in the ratio 1 : √3 : 2.
If the shortest side is x, the other leg is x√3, and the hypotenuse is 2x.
45°-45°-90° Triangle
Also known as an isosceles right triangle. Sides are in the ratio 1 : 1 : √2.
If the legs are x, the hypotenuse is x√2.
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Understanding the Pythagorean Theorem
Learn how the Pythagorean theorem works and how to use it to solve right triangle problems.
Special Right Triangles Explained
A guide to 30-60-90 and 45-45-90 triangles and their unique properties.
Trigonometry Basics for Right Triangles
Introduction to sine, cosine, and tangent ratios in right-angled triangles.