No the graph does not represent a function , it does not pass the vertical line test
The question is incomplete..a , b are two different variables and such can't be solved with only one given interlinked condition.
I think it’s 90 because 180 divided by 2 is 90
PQ is the tangent, therefore you can use a theorem: The arc measure is double the amount of the angle the tangent makes.
So: 62/2=31