algebra word problem - exponential functions

exponential functions - picture frames- since a picture frame includes a border, the picture must be smaller in area than the entire frame. the table shows the relationship between picture area and frame length for a particular line of frames. is this an exponential relationship? Explain.

side length(in.).          picture area (in^2)

 5.                                    6

 6.                                   12

 7.                                   20

 8                                    30

 9.                                   42