The perimeter is the sum of the three sides, and Heron's formula uses the semi-perimeter for area.

Triangle inequality is checked before the area formula is evaluated.

Enter the three side lengths and make sure they can form a triangle. The calculator returns perimeter, area, semi-perimeter, and a basic classification.

1. Enter sides a, b, and c.
2. Check for validity automatically.
3. Read the result card.

For sides 3, 4, and 5, the perimeter is 12 and the area is 6.

The triangle is Scalene Right.

Blank, malformed, zero, and impossible triangle inputs are rejected before any area calculation.

The triangle type label is kept intentionally simple so it matches the data the calculator actually derives.