The table shows the side lengths and perimeters of four squares.

Side Length (x)
Perimeter (y)
4.5
18
8.5
34
10.25
41
13.75
55

Which equation represents the relationship between the side length, x, and the perimeter, y?
y = one-fourth x
y = 4x
y = x + 13.5
y = x – 13.5