No,it's not unique.......
1.Draw a line and cut 5.5cm from it(OK)
2.Construct an angle of any magnitude on one end of it
3.Construct another angle of same magnitude as the supplementary angle of the already drawn angle on the other end of the line(or draw a line parallel to the line forming the angle)
4.Now,u have three lines......find the fourth line by drawing a line parallel to OK