A 2 d triangle........with equal sides......all angles are 60 degrees..................3 60  degree angles.......they sum to 180........but it like full circle...

Equilateral triangle

2D shape

In geometry, an equilateral triangle is a triangle in which all three sides are equal. In the familiar Euclidean geometry, an equilateral triangle is also equiangular; that is, all three internal angles are also congruent to each other and are each 60°