In Fig. 6.5, find the value of x for which the lines l and m are parallel.

Let us draw the figure as below -


It is given to us that l and m are parallel to each other.


Here, n is a transversal intersecting l and m which are parallel to each other.


Also, we have pqm = 44° - - - - (i)


We have to find the value of x, i.e., qpl


We know, if a transversal intersects two parallel lines then each pair of corresponding angles is equal.


Here, the transversal n intersects two parallel lines l and m. So, the following holds true for the corresponding angles.


pqm = npl


npl = 44° (From (i), we have pqm = 44°) - - - - (ii)


Again, the linear pair axiom states that


If a ray stands on a line, then the sum of two adjacent angles so formed is 180°.


Here, we can see that l is a ray standing on the line n.


npl + lpq = 180° (By linear pair axiom)


44° + lpq = 180°


lpq = 180° - 44°


lpq = 136°


x = 136°


Thus, the value of x is equal to 136°.


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