In the given figure lparallel mparallel n , the value of x is

The correct answer is Option (4) → 50°

Three facts are used: angles on a straight line add up to 180°; a line crossing parallel lines makes equal corresponding angles with them; and the angles of a triangle add up to 180°.

• At line n, the angle beside the 120° on the same straight line is \(180^\circ-120^\circ=60^\circ\)

• Since m \(\parallel\) n, the left line makes the same 60° with m (corresponding angles)

• The two slanting lines and m form a triangle with angles 70°, 60° and \(x\), so \(x=180^\circ-70^\circ-60^\circ=50^\circ\)