We are given the values of two angles along two parallel lines.
The relationship of these angles tells us that if we add these two angles, they should equal 180°. So then we can set that equation up:

And then we solve for x:




So now that we know the value of x is 52, we know that the angle whose value is x, is 52°.
To solve for the other angle, we must plug in 52 for x:



And now we know that the value of the other angle is 128°.