Answer:
a=12
Step-by-step explanation:
7a+18=102
7a=102-18
7a=84
a=84/7
a=12 <----- answer
X=34°
Y= 56°
Angle HIF are 90° when we bisectors YI 90-34
Therfore y = 56°
FGI are a triangle sum of it is 180 = 90+56
146 - 180
X= 34