Triangle Area and Perimeter from Three Sides
Enter three side lengths to validate a triangle and calculate its perimeter, area using Heron’s formula, and side-based type.
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Triangle Area and Perimeter from Three Sides
Enter three side lengths to validate a triangle and calculate its perimeter, area using Heron’s formula, and side-based type.
Triangle Area and Perimeter from Three Sides
Enter exactly three finite positive side lengths a, b and c. The tool checks all three strict triangle inequalities before calculating a result.
It returns perimeter, area to five decimal places and a side-based type: equilateral, isosceles or scalene. A 3,4,5 triangle returns perimeter 12 and area 6.00000.
Area is calculated with Heron's formula: s=(a+b+c)/2 and area=square root of s(s-a)(s-b)(s-c). All three inputs must use the same length unit.
The page does not convert units or classify right, acute or obtuse triangles. It does not return angles, altitude, inradius or circumradius.
Calculations use JavaScript floating-point numbers. Nearly degenerate triangles or measurements requiring certified engineering precision should be checked independently.
The implementation uses a stable equivalent of Heron’s formula with sorted sides and scaled large factors. Perimeter uses the input length unit; area uses its square. Only area is normally rounded to five decimals; large values may use scientific notation. Displayed zero can be rounding, not a degenerate triangle. Side equality is exact, without measurement tolerance.
The triangle calculation exceeded the finite numeric range. Adjust the side-length magnitudes.
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