Similarity transformations include dilation and any number of rigid transformations. In a similarity transformation, the ratio of the lengths of corresponding sides in the image and the preimage is equal to the scale factor of dilation. Two or more similar figures will have corresponding sides that are proportional in length.
When you do the inverse operation which in this case would be subtraction you do 54-17 and then you do 17 minus 17 which leaves you with the variable 54-17=34 so k=34
