What is the sum of angles in a triangle?
We usually look at this in a two-dimensional cartesian space , also referred to as 'euclidian geometry'. In that case the sum of angles in a triangle is always 180 degrees.
There are other geometries where this is not necessarily the case. For example in a three dimensional space that is formed as a ball you can have have triangle on the surface of teh ball where the sum of angles is 270 degrees.