So I could be completely wrong, or I could be completely right, but quadrilaterals interior angles equal 360 degrees.
So, if you ad up 98, 72, and 65 you end up with 235 degrees.
In order to find the fourth angle, you would just subtract 235 from 360 and get 125 degrees.
BUT, maybe see if someone else answers too, because I am not 100% sure.