(i) x + 100° = 180° (Adjacent angles are supplementary) x = 80°
z = x = 80º(Opposite angles are equal)
y = 100° (Opposite angles are equal)
(ii) 50° + y = 180° (Adjacent angles are supplementary)
y = 130°
x = y = 130° (Opposite angles are equal)
z = x = 130º (Corresponding angles)
(iii) x = 90° (Vertically opposite angles)
x + y + 30° = 180° (Angle sum property of triangles) 120° + y = 180°
y = 60°
z = y = 60° (Alternate interior angles)
(iv) z = 80° (Corresponding angles)
y = 80° (Opposite angles are equal)
x+ y = 180° (Adjacent angles are supplementary)
x = 180° − 80° = 100°
(v) y = 112° (Opposite angles are equal)
x+ y + 40° = 180° (Angle sum property of triangles)
x + 112° + 40° = 180°
x + 152° = 180°
x = 28°
z = x = 28° (Alternate interior angles)