Which transformations will produce similar, but not congruent, figures?

triangle tuv is rotated 270° clockwise and then translated 12 units down to form triangle t"u"v" .

triangle tuv is rotated 180° counterclockwise and then reflected across the x-axis to form triangle t"u"v" .

triangle tuv is translated 3 units left and 4 units up and then reflected across the y-axis to form triangle t"u"v" .

triangle tuv is dilated by a scale factor of 9 and then translated 2 units right and 1 unit down to form triangle t"u"v" .

In first three options you are talking about , rotation , Translation and Reflection . When you take these qualities into consideration about a triangle neither the shape , nor size of image changes after Rotation, Translation, and Reflection.

So , First three options are incorrect.

And Fourth option→→→ Triangle TUV is dilated by a scale factor of 9 and then translated 2 units right and 1 unit down to form triangle T"U"V"  produces similar figures, which are not congruent.

→T U V ~ T" U" V"→→→→ When Dilation is done two figures are similar. Because in Dilation Either Preimage stretches or Shrank .The Resulting Image is Similar to Preimage.

a reflection across the x-axis , followed by the by a reflection across the y-axis , and then a scale dilation of 0.5 .