Answer:
B x = 7
Explanation:
You know based on the ratio that it's being scaled by 4 times because the one side 4 is 16 in the bigger pentagon.
So if you go the side that matches the one you need to solve, it's 2.5.
2.5 times 4 = 10 so that bigger pentagon side should equal 10.
The equation x-3 = 10
which means x is 7