What is the sum of the angles in a triangle?

The sum of the angles in a triangle is always 180 degrees. This fundamental principle of geometry holds true for all types of triangles, whether they are acute, obtuse, or right triangles. The reasoning behind why this is the case can be illustrated through various methods, such as drawing parallel lines and alternate interior angles or by fitting multiple triangles together to form larger shapes.

Understanding that any triangle's internal angles add up to 180 degrees provides a foundation for more complex geometrical concepts and calculations. This knowledge is essential not only for geometry but also for proofs and theorems related to triangles and their properties.