Geometry Practice Test 3

∠DCE = 180 - 120° [Angles in a straight line are supplementary.]
∠DCE = 60°
∠CED = 180° - 35 - 60° [Angle sum property]
∠CED = 85°
∠CED = ∠FEG [Vertically opposite angles]
So, ∠FEG = 85°
∠a = 180 - 85° - 45°
∠a = 50°