Answer:
2/7 is the scale factor.
Step-by-step explanation:
All you have to do is get two sides that are equal to each other. Let's say Side SR and YX. 3 and 10.5. Do 3/10.5, which is 30/105, which simplified is 6/21, which again simplified is 2/7. So, the scale factor is 2/7.
