The interior angles of any triangle always sum to exactly 180 degrees. This fundamental theorem of Euclidean geometry applies to all triangl...
The interior angles of any triangle always sum to exactly 180 degrees. This fundamental theorem of Euclidean geometry applies to all triangles whether equilateral isosceles scalene right-angled or obtuse. It is frequently used to find unknown angles in triangles and polygons and is foundational for all geometry questions.