Triangle Area & Angle Calculator

Free triangle calculator. Find the area, perimeter, and all missing angles and sides of any triangle given three known values (SSS, SAS, ASA, AAS). Use our free

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Area hesaplanacak
Perimeter hesaplanacak
Angle A hesaplanacak
Triangle Type hesaplanacak

Triangle Formulas

A triangle is defined by its three sides and three angles. Given any three of these six values (with at least one being a side), all other values can be determined using the Law of Sines, Law of Cosines, or basic trigonometry.

Area Formulas

  • Base and height known: A = 0.5 x base x height
  • Heron's formula (three sides known): A = sqrt(s(s-a)(s-b)(s-c)) where s = (a+b+c)/2
  • Two sides and included angle: A = 0.5 x a x b x sin(C)

Triangle Types

By SidesBy Angles
Equilateral (all sides equal)Acute (all angles under 90 degrees)
Isosceles (two sides equal)Right (one 90-degree angle)
Scalene (all sides different)Obtuse (one angle over 90 degrees)

Pythagorean Theorem (Right Triangles)

For a right triangle: a2 + b2 = c2 where c is the hypotenuse (longest side).

Example: sides 3 and 4 → hypotenuse = sqrt(9 + 16) = 5

Common Applications

  • Construction and roofing (calculating rafter length)
  • Navigation (triangulation)
  • Land surveying
  • Engineering and architecture

How to Use This Calculator

Using our calculator is simple: enter the required values into the input fields and click the calculate button. Results are displayed instantly on screen. You can adjust the values and recalculate to compare different scenarios and find the best option for your situation.

Frequently Asked Questions

QuestionAnswer
How accurate are the results?We use standard formulas and up-to-date 2025 rates. Individual circumstances may vary slightly.
Is this calculator free?Yes, completely free and no registration required.
What should I do for exact figures?For precise information, consult a relevant professional or official authority.
Does it work on mobile devices?Yes, it works seamlessly on all devices and screen sizes.

Important Notes

This calculator is provided for informational purposes only. For legal, financial, or medical decisions, always seek advice from qualified professionals. Calculation results do not constitute official documents. Legislative changes may affect results; please visit the relevant official website for the most up-to-date information. Our calculators are regularly updated to reflect current regulations and rates.

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Frequently Asked Questions

For right triangles: a² + b² = c², where c is the hypotenuse (longest side). If a=3 and b=4, then c = √(9+16) = 5.
When you know all three sides: Area = √(s(s-a)(s-b)(s-c)), where s = (a+b+c)/2 is the semi-perimeter.
By sides: equilateral (all equal), isosceles (two equal), scalene (all different). By angles: acute (all < 90°), right (one = 90°), obtuse (one > 90°).