Choose the correct alternative.
In the adjoining figure, if line a || line b and line l is a transversal then find x.
Let us mark the points P and Q on a; R and S on b; A and B on l.
Suppose PQ and AB intersect at M; RS and AB intersect at N.
Since a||b and l is a transversal, then
m∠RNM = m∠SNB (Vertically opposite angles)
⇒ ∠RNM = 2x
Now, m∠RNM + m∠PMN = 180° (Interior angles on the same side of transversal are supplementary)
⇒ 2x + 4x = 180°
⇒ 6x = 180°
⇒ x = `(180°)/6`
⇒ x = 30°
So, the correct answer is option (D).