Calculators > Plane Geometry > Triangle Theorems Calculator

Triangle Calculator:
AAA, ASA, SAS, AAS and SSS Theorems

Choose a Calculation:
Enter
A = Angle Units:
B = Length Units:
   
     
C =

Triangle Shape

Triangle Diagram with Angles A, B and C and sides opposite those angles a, b and c respectively
A = angle A
a = side a
B = angle B
b = side b
C = angle C
c = side c
K = area
P = perimeter

Related Calculator:

Supporting calculations and Triangle Calculator at CalculatorSoup.com

Notes on Triangle Calculations:

The SSS Theorem may produce results as NaN = Not a Number. This is a result of using the Law of Cosines to solve for the unknown angles. See help.

The ASS Theorem, not shown here, requires the use of the quadratic equation and can produce 2 possible results. For more informaition on this and other triangle theorems see:

Weisstein, Eric W. "ASS Theorem." From MathWorld -- A Wolfram Web Resource. http://mathworld.wolfram.com/ASSTheorem.html.

Triangle Theorems:

  • AAA is Angle, Angle, Angle - given the sizes of 2 angles of a triangle you can calculate the size of the third angle. The total will equal 180 degrees.
  • ASA is Angle, Side, Angle - given the size of 2 angles and the size of the side that is in between those 2 angles you can calculate the sizes of the remaining 1 angle and 2 sides. For example, you would enter the values for Angle A, Side c, and Angle B.
  • SAS is Side, Angle, Side - given the size of 2 sides of the triangle and the size of the angle that is in between those 2 sides you can calculate the size of the remaining 1 side and 2 angles. For example, you would enter the values for Side c, Angle B, and Side a.
  • AAS is Angle, Angle, Side - given the size of 2 sides and 1 angle you can calculate the sizes of the remaining 1 angle and 2 sides. For example, you would enter Angle B, Angle C, and Side b.
  • SSS is Side, Side, Side - given the sizes of the 3 sides you can calculate the sizes of all 3 angles in the triangle.