Answer:
x=6
y=9
z=10
Step-by-step explanation: The long 20 on the left has 4, 6 and _10_ to make 20. The blank which is 10 is the same length as z. The proportion of 10/15 translates throughout the whole shape. That means it is 6/9 and 4/6.
The simplified proportion is 2/3 by the way.