Answer :
The answer is that BC and GF are parallel to each other.
Since BC and DF are parallel to each other, and DF and GH are parallel to each other, it's basically like three parallel lines beside each other
Since BC and DF are parallel to each other, and DF and GH are parallel to each other, it's basically like three parallel lines beside each other
If angle BC is parallel to angle DF and angle DF itself to parallel to angle GH then angle GH is parallel to BC.