Answer:
A dilation by a scale factor of 3
Explanation:
Two rectangles or any polygons are said to be congruent if they are exactly same. Dilating a rectangle by scale factor of 3 necessarily means that you are changing the size of the rectangle (either increasing the dimensions by 3 times or decreasing the dimensions by 3 times), so the original rectangle will never have the same shape and size of the dilated rectangle.
Hence, the dilated rectangle and the original rectangle will not be congruent, but rather they will be similar.
But when you are rotating, translating or forming an image of the rectangle by reflection, the resulting rectangle will have the same shape and size of the original rectangle. So, the rectangles are congruent in these cases.
