If the polygons are similar, then the top side is equal to one half of the left side.
Since side (x -1) = 8, then x = 9.
since the lengths of all those four sides are in a 3:2:6:7 ratio, and the whole perimeter is 126, what we do is, simply divide the whole by (3+2+6+7) and distribute accordingly.

Since the hundred place is the 4 and the tens place is higher than 5 ( it is 7) to round to the hundreds place it would be 9500
If it is the question I just completed it should be A. 76.4