Answer:
B. 1/7
Step-by-step explanation:
The triangles are similar, so the ratios of corresponding sides are the same.
... UV/XY = 3/21 = 1/7 . . . . . matches B
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When we talk about the ratio "A to B", we usually mean A:B or A/B. There's the possibility that the question could be interpreted to mean, "what factor do I multiply by to get from A to B?" In that case, the result here would be 7, because XY is 7 times the length of UV.
