How can I solve this problem?

Answer:
116
Step-by-step explanation:
The sum of angles in a quadrilateral is 360°. The figure here is symmetrical about the line NQ, so ∠P = ∠M = x°. Using these facts, we can write ...
∠M +∠N +∠P +∠Q = 360°
x° +28° +x° +100° = 360° . . . . fill in the angle values
2x = 232 . . . . . . . . . . . . . . . . . divide by °, subtract 128
x = 116 . . . . divide by 2