it depends on the length of the quilt as well as the width. If your quilt is 105" or wider, you'll need two widths (or one width of 108" and one of 45"). Then, it also depends on the length of your quilt. If you have a quilt that is longer than 108" you'll need more than three yards. Say your quilt is 100"x120". Then you need one width (108") and at least 3-1/2 yards (126").
Laurie