Theory:

A triangle is a polygon with three vertices, three edges and three angles.
Let us recall some basic notations of a triangle \(ABC\).
 
Theory1.1.png
 
In the above triangle \(ABC\):
  • \(A, B\) and \(C\) are vertices.
  • \(a, b\) and \(c\) are edges (side lengths).
  • \(x, y\) and \(z\) are angles.
Example:
Theory1.2.png
 
In the above triangle \(ABC\):
  • \(A, B\) and \(C\) are vertices.
  • \(8\) units, \(5\) units and \(5\) units are the side lengths.
  • \(94°, 43°\) and \(43°\) are interior angles.