Triangle Calculator

Calculate triangle properties including area, sides, angles, perimeter, and triangle type

Area Calculation

Calculate triangle area using different methods

About Triangles

Triangle Types by Sides

  • Equilateral: All sides equal
  • Isosceles: Two sides equal
  • Scalene: All sides different

Triangle Types by Angles

  • Right: One 90° angle
  • Acute: All angles < 90°
  • Obtuse: One angle > 90°

Key Formulas

  • Area (base×height): ½ × b × h
  • Heron's Formula: √[s(s-a)(s-b)(s-c)]
  • Law of Cosines: c² = a² + b² - 2ab·cos(C)

Triangle Inequality

  • Sum of any two sides must be greater than the third side
  • a + b > c, b + c > a, c + a > b