Triangle Calculator

Calculate triangle properties: area, perimeter, angles, and sides

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Triangle Diagram

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Triangle Formulas

Area (Base + Height)

A = ½ × b × h

Where b is the base and h is the height perpendicular to it.

Heron's Formula

A = √[s(s-a)(s-b)(s-c)]

Where s = (a + b + c) / 2 is the semi-perimeter.

Law of Cosines

c² = a² + b² - 2ab×cos(C)

Used to find the third side when two sides and the included angle are known.