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Triangle Area CalculatorCalculate Area & Perimeter • Base-Height or Heron's Formula • Geometry Tool

Area Calculation
Two Methods
Perimeter Included
Geometry Tool
Quick Example Triangles:
Geometry mathematics

Length of the triangle's base

Perpendicular height from base to opposite vertex

Triangle Geometry Complete Guide

Triangle Properties

Angle Sum: Interior angles sum to 180° (π radians)
Triangle Inequality: Any two sides sum > third side
Area Formula: Area = ½ × base × height
Perimeter: Sum of all three sides

Common Triangle Types

Right Triangle: One 90° angle, a² + b² = c² (Pythagorean)
Equilateral: All sides equal, all angles 60°
Isosceles: Two equal sides and two equal angles
Scalene: All sides and angles different—like most real-world triangles

Area Calculation Methods

Base-HeightArea = ½ × b × h
Heron's Formula√[s(s-a)(s-b)(s-c)]
Right TriangleArea = ½ × leg₁ × leg₂
EquilateralArea = (√3/4) × side²