What is the sum of the exterior angles in a triangle?

Step 1: Recall what is exterior angle
NOTE: An exterior angle of a polygon is an angle outside the polygon
formed by one of its sides and the extension of an adjacent side.
Step 2: Calculate the exterior angles of the triangle at each vertex.
NOTE: The exterior angle theorem states that the exterior angle formed
when you extend the side of a triangle is equal to the sum of its
non-adjacent angles. Remember, our non-adjacent angles are
those that don't touch the angle we are working with.
Step 3: Add all the exterior angles of the triangle.
NOTE: If you count one exterior angle at each vertex, the sum of the
measures of the exterior angles of a polygon is always 360°.