Answer:
°
Explanation:
The angle shown in the figure is known as an external angle.
Also, in a regular polygon (like the regular octagon) the sum of all the exterior angles is the same regardless of the number of sides of the figure:
°
And to find the measure of a single external angle (such as the angle
shown in the figure) we must divide 360 ° by the number of sides n:

and for the regular octagon, since it has 8 sides:

so the value of x is:
°
the measure of angle x is 45° which is the second option