From the given figure, find the angles x and y with proper reasons.

Y equalsto 108 degree due to vertically opposite angle of 108 degree

So another side of Y equals to 72 degree due to linear pair

the sum of three angles of triangle equals to 180 degree
So 40+72+x=180
102+x=180
x= 180-102
x=78
so exterrior X=to 102 degree due to linear pair