Triangle Calculator
Compute area and sides using Pythagorean theorem or Heron's formula. Free online Triangle Calculator for geometry — instant, accurate results, no signup needed.
Derivation
- ├── 01Given
a = 3, b = 4, c = 5 - ├── 02Formula
Heron's: s = (a+b+c)/2; Area = √(s·(s−a)·(s−b)·(s−c)) - ├── 03Semi-perimeter s
(3 + 4 + 5) / 2 = 6 - ├── 04Substitute
√(6 · (6 − 3) · (6 − 4) · (6 − 5)) = √(6 · 3 · 2 · 1) - ├── 05Radicand
36.0000 - ├── 06Area6.0000
- ├── 07Perimeter3 + 4 + 5 = 12.0000
- └── 08Pythagorean check
3² + 4² = 25; 5² = 25 → equal ✓ right triangle
Pythagoras of Samos (c. 570–495 BCE) likely wasn’t the first to find a²+b²=c² — Babylonian tablets from ~1800 BCE used it — but the first rigorous proof is credited to his school.
Understanding the Triangle Calculator
The Triangle Calculator helps you compute compute area and sides using pythagorean theorem or heron's formula.. It runs entirely in your browser with no sign-up required.
Geometry is what turns raw measurements into useful answers about space — how much paint, how big a yard, how much material a project will need. Every craftsperson, architect, and DIYer reaches for these formulas regularly. The Triangle Calculator sits in that toolkit — it compute area and sides using Pythagorean theorem or Heron's formula. Enter your numbers above and the result updates instantly; every step of the math is shown in the Derivation panel so you can see exactly how the answer was reached.
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