Answer:The angle measures remain same from the preimage to the image.The side lengths measures remain same for the preimage to the image.This is an example of rigid transformation.Step-by-step explanation:Consider ΔABC and ΔA'B'C'AC=A'C'=2 units (as drawn)BC=B'C'=2 units (as drawn in graph)∠ACB=∠A'C'B'=90°Therefore, by Side Angle Side(SAS) axiom of congruency ΔABC and ΔA'B'C' are congruent.In congruent triangles, side lengths and angle values are equal to each other.∴The angle measures remain same from the preimage to the image.The side lengths measures remain same for the preimage to the image.If the side lengths remain the same in a transformation it is known as rigid transformation, therefore it is also a rigid transformation due to the reflection by line l.