Question

does an isometry preserve congruence?

Answer 1

true
isometry is an exact transformation of a shape. which means that it is congruent to the object.
isometries preserve length

Answer 2

yes, that is basically the definition of an isometry

Answer 3

it has to do two things

1), preserves length

2), preserves angles

Answer 4

so once a figure goes through an isometry,

1), the size does not change
2), the shape does not change

so they are still congruent figures