Why under transformation a figure is always congruent to its image?

A figure is always congruent to its image under transformation because congruence means that the two figures have the same shape and size. Transformations such as translations, rotations, and reflections preserve the lengths of sides and the measures of angles, ensuring that the original figure and its image maintain their geometric properties. Therefore, any transformation applied will result in an image that is congruent to the original figure.