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Triangle Calculator
Choose the measurements you know. The triangle, results and worked steps update as you type. Base and height alone determine area only.
Choose the measurements you know. The triangle, results and worked steps update as you type. Base and height alone determine area only.
Dimensions
Live geometry diagram
Results update as you type.
Results
Base and height determine area, but not the other sides, perimeter or angles. For a right triangle, use the two-legs method.
How it was calculated
A = √(s(s−a)(s−b)(s−c))P = a+b+cr = A/sR = abc/(4A)hₐ = 2A/a∠A+∠B+∠C = 180°
How to use the triangle calculator
Choose a method and enter its known measurements. Side lengths must be positive. The completed triangle and calculation steps appear automatically.
Can base and height determine a triangle?
No. Base and height determine the area only. The apex can move sideways, changing the other sides, perimeter and angles without changing that area.
Geometry formulas
SSS: A = √(s(s−a)(s−b)(s−c))
SAS: c² = a²+b²−2ab cos C
AAS/ASA: a/sin A = b/sin B = c/sin C
Right triangle: two legs: c² = a²+b²
Triangle: base and height: A = b×h/2
How to use the triangle calculator
How to use the triangle calculator
Choose a method and enter its known measurements. Side lengths must be positive. The completed triangle and calculation steps appear automatically.
Can base and height determine a triangle?
No. Base and height determine the area only. The apex can move sideways, changing the other sides, perimeter and angles without changing that area.
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