Since it is proportional, whatever values we get in the other shape can be used to compar with the first.
As we can see, 5 is proportional to the 10 in the first shape.
Which means we have to manipulate the 10 to get 5
10/2=5
So we now know that the other shape is the first but divided by 2
15/2= 7.5
X = 7.5
