Question

answer
figure uvwx congruent to figure lmno because rigid motions be used to map figure uvwx onto figure lmno.
figure uvwx similar to figure lmno because rigid motions and/or dilations be used to map figure uvwx onto figure lmno

Explanation:

Congruent figures are identical in shape and size, and can be mapped onto each other using only rigid motions (translation, rotation, reflection). Similar figures have the same shape (proportional sizes) and can be mapped using rigid motions plus dilations. Figure UVWX is smaller than Figure LMNO, so rigid motions alone cannot map them (they are not congruent). However, a dilation (to scale UVWX to match LMNO's size) plus rigid motions can map UVWX onto LMNO, so they are similar.

Answer:

Figure UVWX is not congruent to Figure LMNO because rigid motions cannot be used to map Figure UVWX onto Figure LMNO.
Figure UVWX is similar to Figure LMNO because rigid motions and/or dilations can be used to map Figure UVWX onto Figure LMNO.