Given that,
l ‖ m
Let, l ‖ m and transversal cuts them and
∠1 = 70°
∠3 = 20°
∠4 = 30°
∠1 + ∠2 = 180°(Interior angle)
∠2 = 110° (i)
∠2 = ∠5 (Vertically opposite angle)
∠5 = 110° (ii)
∠5 + ∠3 + ∠4 = 180°(Sum of angles of a triangle is 180 o )
110° + x + 30° = 180°
x = 40°