Perimeter of a Triangle Calculator
Calculate the perimeter and other properties of a triangle using the lengths of its sides.
Triangle Properties
Formulas
- Perimeter: P = a + b + c
- Semi-perimeter: s = P/2
- Area (Heron's formula): A = √(s(s-a)(s-b)(s-c))
- Angles (Law of Cosines): cos(α) = (b² + c² - a²)/(2bc)
Triangle Types
- Equilateral: All sides equal
- Isosceles: Two sides equal
- Scalene: All sides different
- Right: One angle is 90°
- Acute: All angles < 90°
- Obtuse: One angle > 90°
Note: The sum of any two sides must be greater than the third side (Triangle Inequality Theorem).
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