The angles of a triangle must always sum to:

The sum of the angles in any triangle is always 180 degrees. This is a fundamental property of Euclidean geometry, which is the type of geometry most commonly taught in schools and used in practical applications. When you draw a triangle, regardless of its type (scalene, isosceles, or equilateral), measuring the internal angles will always yield a total of 180 degrees.

This property can be demonstrated through several methods, including constructing a triangle and using parallel lines or decomposing it into simpler shapes, like a rectangle or other triangles. Understanding this principle is crucial for various applications in engineering and higher mathematics, as it forms the basis for further explorations into polygons and trigonometry.