Answer: Tiffany can be certain the trapezoids are congruent.
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:
- Rotation: the figure is turned around a fixed point;
- Reflection: is created by fliping over the figure over a line;
- Translation: move the figure to another location, without changing its size;
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.