What is the sum of the internal angles of a triangle in the open universe? "Flat Geometry. This is the geometry we learned in school. The angles of a triangle add up to 180 degrees, and the area of a circle is πr2. The simplest example of a flat three-dimensional shape is ordinary infinite space — what mathematicians call Euclidean space — but there are other flat shapes to consider too." This study therefore states that a triangle in the open universe could be like in the flat one.
