Since the whole figure including all the points is enlarged at the same time, the dilated figure will still have the same slope and that includes the fact that point T is still in line Y'Z'. The slope or shape does not change, only the size alters.The center of dilation is still at Point T in this case.
There’s not much that’s happening on Y'Z'¯¯¯¯¯¯¯
because nothing has changed on its slope and shape. However, its shape seems to
change. I am hoping that this answer has satisfied your query and it
will be able to help you in your endeavor, and if you would like, feel free to
ask another question.