The rule of a geometric sequence:
We have:
Find 
substitute:
Assuming that the figures given are square such that the scale factor between them is equal to 28/8 which can be further simplified into 7/2. The ratio of the perimeter is also equal to this value, 7/2. However, the ratio of the areas is equal to the square of this value giving us an answer of 49/4.
ABC and DBC is Side Angle Side
They would be equal here!
So, 6x - 2 = 10x - 30
= 10x - 6x = 30 - 2
4x = 28
x = 28/4
x = 7
In short, Your Answer would be 7
Hope this helps!
