Triangle Calculator

Calculate sides, angles, area, and more for any triangle by entering three known values (including at least one side).

a b c α β γ

Understanding Triangle Calculations

Triangles are fundamental shapes in geometry with three sides and three angles. Every triangle's internal angles sum to 180°.

Key Triangle Properties

  • Area: Calculated using base × height ÷ 2 or Heron's formula
  • Perimeter: Sum of all three sides
  • Pythagorean theorem: For right triangles, a² + b² = c²