What is a key characteristic of rigid transformations?

A key characteristic of rigid transformations is that they preserve size and shape. This means that when a shape undergoes a rigid transformation—such as a translation, rotation, or reflection—the resulting figure remains congruent to the original figure. The distances between points, angles between lines, and overall dimensions do not change during these transformations, allowing the transformed figure to maintain the same geometric properties as the original.

This concept is fundamental in geometry, as rigid transformations enable us to compare figures and determine congruence without altering their structures. The preservation of size and shape differentiates rigid transformations from non-rigid transformations, which can affect the scale of the figure, changing its area and possibly altering angles as well.