1. According to the meaning of the question, angle OAB= angle Oba and angle OAC= angle Orca, so angle BOC= 180- (angle OBC+ angle OCB)= 180-

[180-(OAB angle+Oba angle+Oka angle +OAC angle)] =180-(180-104) =104 degrees.

2. because AG is an angular bisector, the angle of e AG is DAG. And because EG is parallel to AD, ∠EGA =∠ Gard, so ∠EGA=∠EAG. If E is used and EF is perpendicular to AC and F, then EF=GD, and then GD = GE=EF = EA= 1/2.