The small polygon is a regular hexagon so each internal angle = 120 degrees while the large polygon is a regular octagon with internal angle =
135 degrees.
So angle x = 360 - ( 120 + 135)
= 360 - 255
= 105 degrees.
Note we use the fomula T = 180( n - 2) to find total internal angles in an n sided polygon. So for hexagon T = 180(6-2) = 180*4 = 720 so each internal angle in a regular hexagon = 720/6 = 120 degrees.
