PROPERTIES OF TRIANGULES

 

A triangle can be defined as a polygon with three sides, or as a polygon with three vertices. The triangle is the simplest polygon and the only one that does not have a diagonal. Three non-aligned points always define a triangle (both in plane and in space).

Every triangle has 3 sides, 3 vertices, and 3 interior angles. Their specific name is TRIGON, although they have been commonly called TRIANGLES, a form that has spread and is how most people know them.

The sum of the three interior angles of a triangle is always 180°

EXAMPLE

Given the following figure determine the missing interior angle, since two of its measurements are known.