The sum of angles in a triangle is always 180 degrees. This fundamental principle of Euclidean geometry applies to any triangle, regardless of its type – be it acute, obtuse, or right-angled. Understanding this concept is crucial in various fields, such as mathematics, architecture, and engineering, as it serves as a foundation for more advanced geometric principles. When you add up the three interior angles of a triangle, they will invariably equal 180 degrees, confirming the relationship between angles and shape in planar geometry.