Answer:
In fig. 9, angle Y = angle 110° (vertically opposite angles )
Angle x = angle z = 180 - 110 = 70° (angles on a straight line)
In fig 10, angle y = 78°
Angle x = angle z = 180-78 = 102°
In fig 11, angle x = 83°
Angle y = angle z = 180-83 = 97°
In fig 12, angle y = 37°
Angle x = angle z = 180-37 = 143°
