Since the only two corresponding side you have are 10 units and 4 units, you can divide these two numbers to get the scale factor.
10÷4=2.5
next you find the sides corresponding to X Y and Z and if it is on the bigger figure you divide, if it is on the smaller side you multiply
X corresponds with 5 (so ×2.5)
Y corresponds with 8 (÷2.5)
Z corresponds with 10 (÷2.5)
final answer is X=12.5 Y=3.2 Z=4
I try to explain the question and give the answer, I hope this helps!