A cyclist rolls down a hill. He starts from rest and after 8 s he is traveling at 13.6m/s. What is his acceleration?

Suppose you are analyzing the relationship between time and distance given in a table, and there are 4 values for each quantity. you divide distance 2 minus distance 1 by time 2 minus time 1.you then divide distance 4 minus distance 3 by time 4 minus time 3 and get a different answer. what can you say about the relationship?