I have quadrilateral that has the angle measures: 130, 92, and 70. It asks me if Ia circle can be circumscribed in there. How do I know if it can or can't?

Now I need help with these Imageshack - asdjw.jpg

I'm supposed to find the indicated arc or angle measure. For the first on how would I find arc AB and the second how do I find angle A?

Thanks for your help guys.

Also I was wondering has anyone ever done those big,bigger,biggest circle puzzle? I would like to double check my answers with anyone if possible.