The relationship between the number of months and cumulative cell phone cost is represented by the scatter plot shown.
Cumulative Cost
600
500
2 400
Cumulative Cell Phone Cost (dollars)
(10, 504)
(9,470)
(8,418).
(7, 361)
(6, 324)
.(5, 253)
(3, 162) •(4, 196)
300
200
100+(1,55) (2, 108)
8
9
10
Number of Months
A line of best fit for this data is C = 51m + 4.4, where is the cumulative cell phone cost and m is the number of months.
Using this data, which value is the best prediction of the cumulative cell phone cost after 18 months?