Triangle Calculator
Worked example result
| Area | 6.0000 |
| Perimeter (three-sides mode) | 12.0000 |
| Semi-perimeter (three-sides mode) | 6.0000 |
The 3-4-5 triangle: perimeter 12, semi-perimeter 6, and Heron's formula gives √(6 × 3 × 2 × 1) = √36 = 6 for the area — matching (3 × 4) ÷ 2 from the base–height method.
Base–height: Area = (b × h) ÷ 2 · Heron: Area = √(s(s−a)(s−b)(s−c)), where s = (a+b+c) ÷ 2 · Powered by CalcHub — Triangle Calculator