What is the value of y?

45*

For this we’ll only use the top most angles.
We have a straight across line, which is equal to 180*.
That is then cut in half making it a 90* shown by the box.
That makes the others side 90* before it’s cut.
Then it’s cut in half. 90/2=45

45*

The answer would be (c)

The answer to your question is 1/9