A translation only moves vertically or (and) horizontally our image.
This means that a translation does not change the size
A translation does not rotate the image.
Then a translation of triangle 1 needs to have the same size than triangle 1, and the same "direction" (in triangle 1 we can see that the hypotenuse is at the right side, then in the translated triangle we also should have the hypotenuse at the right side).
Then the only option that seems correct is triangle 4
