Answer 1

The given figure is as follows with : l || m

Also, ∠1 and ∠2 form a linear pair. Thus,

∠1 +∠2 = 180°

It is given that ∠2 = 90°, substituting this value , we get :

∠1 + 90° = 180°

          ∠1 = 180° - 190°

           ∠1 = 90°      (i)

In a triangle, we know that, the exterior angle is equal to the sum of the interior opposite angle.

In ΔAOB:

x + ∠1 = 125°

 x = 125° - ∠1

From equation (i):

 x = 125° - 90°

 x = 35°