The sentence that best explains why shape 1 and shape 2 are not congruent is:
therefore correct option is (5).
5) There is no sequence of rigid transformations that will map shape 1 onto shape 2.
Congruent shapes must be the same size and shape, which means one shape can be mapped onto the other using rigid transformations, which include rotations, reflections, and translations (and not dilations, as they can change the size of the shape). If shape 1 cannot be mapped onto shape 2 using any sequence of these rigid transformations, then they are not congruent.
The other statements involve conditions that are either not sufficient to prove non-congruence (such as the perpendicularity or parallelism of corresponding sides) or include a non-rigid transformation (dilation), which is not used when determining congruence.