Answer:
x = 60
Explanation:
<DGC = 90 degrees Given
<AGB = <DGC Vertically opposite angles.
<AGB = 90 degrees. <AGB takes on the properties of <DGB
30 + x + 90 = 180 The three angles make up a line.
120 + x = 180 Combine like terms..
x = 180 - 120 Subtract 120 from both sides
x = 60