What is the sum of the angles in a triangle?

The sum of the angles in a triangle is 180 degrees, which is a fundamental property in Euclidean geometry. This means that if you take any triangle, regardless of its shape (scalene, isosceles, or equilateral), the three internal angles will always add up to exactly 180 degrees.

This property can be demonstrated through various methods, such as drawing a triangle and extending one of its sides, or by using parallel lines and alternate interior angles. This consistent rule is crucial for solving many problems related to triangles, including finding unknown angles when two angles are known.

The other given options represent sums of angles relevant in different contexts or shapes. For instance, 360 degrees is the sum of angles around a point (full rotation), while 90 degrees is the sum of angles in a right angle or in quarters, and 270 degrees does not have a direct relevance to triangle angle sums. Thus, the unique property of triangles being that their internal angles always sum to 180 degrees stands as the correct response.