We've had a few reports similar to the following: "Sometimes, when doing a Similarity and Transformations problem, the shapes just won't fit no matter how many dilations, reflections, etc I do."
Sometimes when there has been a number of modifications to a shape, it won't ever line up perfectly, and will always be just ever-so-slightly off from the correct positioning. This usually occurs after a good number of changes have been applied, so to get around it simply reset the shape and start from its original position and shape.
This should allow you to complete the problem, as long as you don't use too many steps. If you've tried this workaround and still can't complete it, please let us know in the Technical Issues forum.
Internal ticket: 170186233658984