Question

Which transformations will produce similar, but not congruent, figures? ​ Triangle PQR ​ is rotated 180° counterclockwise and then translated 11 units left to form ​ triangle P"Q"R" ​ . ​ Triangle PQR ​ is rotated 90° clockwise and then reflected across the y-axis to form ​ triangle P"Q"R" ​ . Triangle PQR is reflected across the x-axis and then rotated 90° clockwise to form triangle P"Q"R" . ​ Triangle PQR ​ is reflected across the y-axis and then dilated by a scale factor of 6 to form ​ triangle P"Q"R" ​ .

Answer 1

Two or more triangles are said to be congruent if and only if their corresponding sides are equal in length, and when the corresponding sides are equal, it follows that their corresponding angles will also be equal in measure.
Two or more triangles are said to be similar if and only if the ratios of their corresponding sides are equal in length, and when the ratios of the corresponding sides are equal, it follows that their corresponding angles will also be equal in measure.
From the explanations above, we can see that rotation and reflection will produce congruent triangles (figures). The transformation that will produce similar but not congruent figures is dilation (or enlargement). 

So, the correct answer is> Triangle PQR  is reflected across the y-axis and then dilated by a scale factor of 6 to form  triangle P"Q"R"  .
Triangle P"Q"R" will be larger but similar to triangle PQR