Triangle Calculator
Calculate triangle properties including area, perimeter, angles, and side lengths. Supports various triangle types and calculation methods for comprehensive geometric analysis.
Triangle Input
Enter Three Sides
Quick Presets
Triangle Properties
Basic Properties
Side Lengths
Angles
Triangle Classification
Additional Properties
Heights (Altitudes)
Medians
Triangle Types & Classifications
Classification by Angles
Classification by Sides
How the Triangle Calculator Works
Calculation Methods
Law of Cosines:
Law of Sines:
Heron's Formula (Area):
where s = (a+b+c)/2
Additional Formulas
Circumradius:
Inradius:
Altitude:
Example Calculations
Right Triangle (3-4-5)
Equilateral Triangle (side = 6)
Frequently Asked Questions
What is the triangle inequality?
The triangle inequality states that the sum of the lengths of any two sides of a triangle must be greater than the length of the third side. This must be true for all three combinations of sides.
When is the SSA method ambiguous?
The SSA (Side-Side-Angle) method can be ambiguous when the given angle is acute and the side opposite to it is shorter than the other given side. This can result in two possible triangles.
How accurate are the calculations?
Our calculator uses precise mathematical formulas and provides results accurate to several decimal places. However, for practical applications, consider rounding to appropriate significant figures.