Please can someone help geometry honors

Find the cosine function that is represented in the graph.

Use the distance formula to find the distance between (-3,5) and (3,1)

The scatter plot shows the number of animal cells clara examined in a laboratory in different months: plot ordered pairs 1, 20 and 2, 60 and 3,100 and 4, 140 and 5, 180 what is the approximate predicted number of animal cells clara examined in the 9th month?