Question
How does this triangle calculator find area?
It uses Heron's formula from the three side lengths, and it can also compare against the base-height area formula if you provide a height.
Math
Use OmniCalc's triangle calculator to calculate triangle area, perimeter, semiperimeter, and side-based type from three side lengths, with an optional height check.
Triangle calculator
Enter three sides to calculate perimeter, semiperimeter, Heron area, and side-based triangle type. Add a height to compare with the base-height area formula too.
Why this result matters
A broad geometry entry page that builds on the new slope and Pythagorean branch while capturing general triangle intent. Use the tool above to enter a few clear inputs and get a practical answer you can use right away.
This triangle calculator helps students and everyday users find triangle area, perimeter, semiperimeter, and triangle type quickly. Enter three sides to use Heron's formula, and add a height if you want a base-height area check too.
Formula and method
The calculator uses the triangle perimeter formula, semiperimeter, and Heron's formula for area, with optional base × height ÷ 2 comparison when a height is available.
Example
If you enter sides 5, 5, and 6 with height 4.8, the calculator returns perimeter 16 and area 12.
FAQ
Short answers to the questions people often ask before or after using the tool.
Question
It uses Heron's formula from the three side lengths, and it can also compare against the base-height area formula if you provide a height.
Question
It identifies equilateral, isosceles, and scalene triangles from the three sides.
Question
The three side lengths must all be positive and satisfy the triangle inequality, so any two sides together must be longer than the third.
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