Question

In the figure, ∠1 = 60° and ∠6 = 120°. Show that the lines m and n are parallel.

Answer 1

According to the question,

We have from the figure ∠1 = 60° and ∠6 = 120°

Since, ∠1 = 60° and ∠6 = 120°

Here, ∠1 = ∠3 [since they are vertically opposite angles]

∠3 = ∠1 = 60°

Now, ∠3 + ∠6 = 60° + 120°

⇒ ∠3 + ∠6 = 180°

We know that,

If the sum of two interior angles on same side of l is 180°, then the lines are parallel.

Therefore, m || n