Question

In the following figure, state which pair of lines are parallel. Give reason.

Answer 1

We have,

∠1 = 120°  ...[Vertically opposite angles]

Now, 60° + ∠1 = 60° + 120° = 180° and these angles are interior angles on the same side of transversal l.

Thus, m || n as the sum of co-interior angles is 180°.