<h3><u>The function used to find the perimeter of a square, represented by y, given the length of a side, represented by x is: y = 4x</u></h3>
<em><u>Solution:</u></em>
Let "y" be the perimeter of square
Let the length of side be "x"
From given,
The perimeter of a square is the product of four and the length of a side
Which means,

Substituting the given variables,

Thus perimeter of square is y = 4x