7x + 10 + 15x + 16 = 180 (angles adjacent to each other in a //polygon are supplementary)
22x = 154
x = 7deg
This is a question on polygons and angles. If you wish to venture further into it/understand this topic better, you may want to follow my Instagram account (learntionary), where I post some of my own notes on certain topics and also some tips that may be useful to you :)