In the figure on the left side upper corner, you can see two parallel lines that are crossed by a transversal line and you can identify the missing angles x and y.

The pair of angles y and `66^o` are corresponding angles and they are equal, such that: `y = 66^o` .

You can evaluate the missing angle x, such that:

`x = 180^o - 78^o = 102^o`

In the figure on the right side upper corner, you may notice that the pair of angles x and `180^o - 121^o` are are corresponding angles, hence, they have equal measures.

`x = 180^o - 121^o`

`x = 59^o`

You may evaluate the angle y using the property of internal angles in triangle, such that:

`y = 180^o - (180^o - 112^o + 59^o)`

`y = 112^o - 59^o => y = 53^o`