Can someone explain what these types of arrows mean please?

Which system of linear inequalities is represented by the graph?

Based on the figures as marked, /\rqs = —

1) in triangle the, what is the measure of angle t (in degrees)? 2) in triangle bat, the measure of angle b is 66∘, and the measure of angle t is 77∘.what is the measure of the exterior angle at a (in degrees)?