Question

What is the value of x? 45 30 90 85

Answer 1

I would say 30 degree since each opening has a different size.
It's a Right Triangle making Z = 90 degree so you rule out 85 degree and 90 degree. The only other choice you have are 45 and 30. 
For the answer to be 45 degree it would mean that two of your opening would be the same size, however that is not the case here.
30 degree
Looks like a 30-60-90 Triangle

Answer 2

The answer is 45 degrees.

Explanation: angle x is an inscribed angle. The measure of these are half the measure of the intercepted arc.

Angle x intercepts the arc that has a measure of 90 degrees, therefore x is 45 degrees.