For this case we have by definition, that the sum of the exterior angles of a polygon is equal to 360 degrees, only when considering only one exterior angle for each vertex of the polygon, regardless of the number of sides it possesses. That said we have to:
The external angle of a regular polygon is given by:
Where:
n: It is the number of sides of the polygon
Then, for a nonagon each exterior angle will measure:
Answer:
40 degrees each exterior angle
360 degrees the sum