Trapezoid QRST is dilated by a scale factor of 3.4 to create trapezoid Q’R’S’T’. The perimeter of trapezoid QRST is y units. What is the perimeter in units of trapezoid Q’R’S’T’?
Since the trapezoid is dilated by a scale factor of 3.4, this means that every length in trapezoid Q’R’S’T’ is 3.4 times the length of the corresponding side in trapezoid QRST.
Therefore, the perimeter of trapezoid Q’R’S’T’ is 3.4 times the perimeter of trapezoid QRST.
So, the perimeter of trapezoid Q’R’S’T’ is 3.4y units. Answer: \boxed{3.4y}.