What is the sum of the measures of the exterior angles of a nonagon?

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:

40 degrees each exterior angle

360 degrees the sum

(5, 4) = (x, y)

to get the unit rate we need to divide/simplify the relationship:

4 ÷ 5 = 0.8

1 pound of potatoes cost 0.8$