Supplementary angles are angles that are adjacent to each other and when summed to get a total of 180 degrees. In this case, DEF and FEG are supplementary. Thus the equation is <span>9x +1 + 8x + 9 = 180 = 17 x + 10; x then is equal to 10 so <</span>DEF = <span>9*10 +1 =91 degrees </span><FEG = <span>8*10 + 9 = 89 degrees</span>