Triangle calculator - area and angles
Calculate a triangle's area, angles, perimeter and height from its three sides.
Enter the three sides of the triangle
Area
6 m²
Perimeter: 12 m
Angle α (opposite side a)36.87°
Angle β (opposite side b)53.13°
Angle γ (opposite side c)90°
Height to side a4 m
Calculations are based on Estonia's tax rates in force for 2026. Results are informational.
Last updated: 2026-06-03
How is a triangle solved?
From the three sides the area is found with Heron's formula: S = √(s(s−a)(s−b)(s−c)), where s is the semi-perimeter. The angles come from the law of cosines. A triangle exists only if the sum of any two sides is greater than the third.
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