Velocity-Time Graph_1.3

A physics student with a strong interest in analyzing motions spots a dog making a chase in a straight line. The student uses a coordinates system where the motion is parallel to the x-axis and to the right is the +x direction. The student makes measurements of the dog's motion and constructs a graph of velocity as a function of time. Determine the following:
the dog's velocity at 2.5 s.
the dog’s velocity at 6 s.
the total distance dtotal covered during the interval t = 0 → 7 s
the average speed savg during the interval t = 0 → 7 s.
the average velocity vavg during the interval t = 0 → 7 s.
the average velocity vavg during the interval t = 2 → 6 s.
the average velocity vavg during the interval t = 1.2 → 3.7 s.