Right Triangle Calculator

Calculate missing sides, angles, area, and perimeter of right triangles using various input combinations. Perfect for trigonometry, geometry, and engineering applications.

Right Triangle Solver

Common Right Triangle Examples

Click on these links to see instant calculations with common right triangles:

Right Triangles

A right triangle has one 90-degree angle and follows the Pythagorean theorem. The relationships between sides and angles are governed by trigonometric ratios, making them fundamental in geometry and trigonometry.

Right Triangle Formulas

Pythagorean Theorem: a² + b² = c²
Area = (1/2) × base × height
Perimeter = a + b + c
sin(θ) = opposite / hypotenuse
cos(θ) = adjacent / hypotenuse
tan(θ) = opposite / adjacent

Special Right Triangles

Triangle Type Angles Side Ratios Example
45-45-9045°, 45°, 90°1 : 1 : √21, 1, 1.414
30-60-9030°, 60°, 90°1 : √3 : 21, 1.732, 2
3-4-536.87°, 53.13°, 90°3 : 4 : 53, 4, 5
5-12-1322.62°, 67.38°, 90°5 : 12 : 135, 12, 13
8-15-1728.07°, 61.93°, 90°8 : 15 : 178, 15, 17
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  • Surveying: Measure land areas, heights, and distances using triangulation

Frequently Asked Questions

What is a right triangle?

A right triangle is a triangle with one 90-degree angle. It has three sides: two legs (adjacent to the right angle) and a hypotenuse (the longest side opposite the right angle).

How do you find the missing side of a right triangle?

Use the Pythagorean theorem (a² + b² = c²) for sides, or trigonometric ratios (sin, cos, tan) when you have an angle and one side. The method depends on what information you have.

What are the trigonometric ratios in a right triangle?

The three main ratios are: sin(θ) = opposite/hypotenuse, cos(θ) = adjacent/hypotenuse, and tan(θ) = opposite/adjacent, where θ is one of the acute angles.

See Also