Triangle Calculator
Calculate triangle area, perimeter, angles, and sides
What Is a Triangle Calculator?
A triangle calculator helps you find the missing sides, angles, area, and perimeter of a triangle. Whether you're solving right triangles or working with any triangle, this tool handles various inputs to give you accurate results.
How to Use
- Select the triangle type (Right Triangle, Base & Height, Three Sides, or Side & Angle)
- Enter the known measurements based on your selection
- Click "Calculate" to see your results
Examples
Right Triangle
Side A (Base): 3
Side B (Height): 4
Hypotenuse (Side C): 5
Area: 6
Perimeter: 12
Angle A: 36.87°, Angle B: 53.13°
Triangle Types
Right Triangle
One angle is 90°. Use the Pythagorean theorem: a² + b² = c².
Equilateral Triangle
All sides equal, all angles 60°.
Isosceles Triangle
Two sides equal, two angles equal.
Scalene Triangle
All sides and angles are different.
FAQs
What is the Pythagorean theorem?
In a right triangle: a² + b² = c², where c is the hypotenuse.
How do I find the area of a triangle?
Area = (base × height) / 2. For right triangles, area = (a × b) / 2.
What is the triangle inequality theorem?
The sum of any two sides must be greater than the third side.