Triangle Calculator
Right Triangle
Three Sides (SSS)
Two Angles (ASA)
Side-Angle-Side (SAS)
Equilateral
Isosceles
About Triangles
A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. Triangles can be classified by their sides (equilateral, isosceles, scalene) or by their angles (acute, right, obtuse).
Triangle Formulas:
| Calculation | Formula |
|---|---|
| Area | (base × height) / 2 |
| Pythagorean theorem | a² + b² = c² (for right triangles) |
| Law of Sines | a/sin(A) = b/sin(B) = c/sin(C) |
| Law of Cosines | c² = a² + b² - 2ab cos(C) |
| Perimeter | a + b + c |
| Sum of angles | A + B + C = 180° |
Triangle Types:
| Type | Description |
|---|---|
| Equilateral | All sides equal, all angles 60° |
| Isosceles | Two sides equal, two angles equal |
| Scalene | All sides and angles different |
| Right | One 90° angle, satisfies Pythagorean theorem |
| Acute | All angles less than 90° |
| Obtuse | One angle greater than 90° |
Triangle Solving Methods:
- SSS (Side-Side-Side): When all three sides are known
- SAS (Side-Angle-Side): When two sides and the included angle are known
- ASA (Angle-Side-Angle): When two angles and the included side are known
- AAS (Angle-Angle-Side): When two angles and a non-included side are known
- HL (Hypotenuse-Leg): For right triangles when hypotenuse and one leg are known