Question

in fig 6.6 which of the two lines are parallel and why?

Answer 1

Hey friend!!!
In the 1st figure the parallel lines are l and m, this is because the co-interior angles are supplementary .i.e., 132°+48°=180°

Similarly in 2nd figure, there are no parallel line because the co-interior angles are not supplementary. i.e., 73°+106°=179° which is not equal to 180°

HOPE IT HELPS....

Answer 2

In fig 1
Here ,132°+48°=180°
(sum of interior angles of same side of transversal)

If a transversal intersects two parallel lines then each pair of interior angles on the same side of the transversal is supplementary i.e 180°

Hence l parallel to m

In fig 2

P & Q are not parallel because the sum of interior angles on the same side of a transversal is not equal to 180°

73°+106° is not equal to 180°