Answer:
10.5
Step-by-step explanation:
ΔXYZ is similar to ΔABC. So the corresponding sides are proportional:
XY / AB = XZ / AC = YZ / BC
We want to find length AB, so we can either use the first proportion:
7 / k = 3 / 4.5
Or we can use the second proportion:
7 / k = 6 / 9
Either way, we'll get the same answer. I'll use the second proportion. Cross multiplying:
6k = 63
Dividing:
k = 10.5
