Area of a Triangle

A = ½·a·h — main formula, Heron's formula, and practice trainer.

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Triangle Area — Key Formulas

Main formula: A = ½ × base × height = ½·a·h
Right triangle: A = ½·a·b (legs a and b)
Heron's formula: A = √(s(s−a)(s−b)(s−c)), s = (a+b+c)/2
Using sine: A = ½·a·b·sin C
Area is measured in square units: cm², m²

Frequently Asked Questions

What is the formula for the area of a triangle?

A = ½ × base × height = ½·a·h, where h is the height drawn to base a.

What is Heron's formula?

A = √(s(s−a)(s−b)(s−c)), where s = (a+b+c)/2 is the semi-perimeter.

How to find the area of a right triangle?

For a right triangle with legs a and b: A = ½·a·b.