Answer:
x=14
Explanation:
This is asking for the ratio of A to B.
The x-10 is 1.
The 28 is 7.
Find the scale factor by executing 28/7=4.
So, you would want polygon A to be 4 in order to be proportional to polygon B.
Now, you can just guess and check that 14-10=4
Or, you can set up the equation as follows: x-10 = 4
+10 +10
x = 14 is your answer.