the answer would be 168 because since there is a right angle which is 90 degrees and there is the angle that is 78 degrees yu would add them. and then you would take your sum which is 168 degrees and subtract that from 180. because all triangles are 180 degrees. and you would get 12 degrees. and since you are trying to find the 1 which is a part of that line and all lines are 180 degrees, you would subtract 12 from 180 and you get 168 degrees.
