Answer: Tiffany can be certain the trapezoids are congruent.
Step-by-step explanation: Two figures are congruent when their corresponding angles are equal and they have the same shape and size.
A figure can go thorugh 3 types of transformations:
As long the figure doesn't change its size or shape, it doesn't matter if it's rotated, reflected or translated, they will be congruent.
When the trapezoid was rotated creating another one, the two shapes didn't change its size or shape, so Tiffany can be certain they are congruent.