Answer:
1
Explanation:
in this constellation the upper left vertex corresponds to the bottom right vertex. and the upper right vertex to the bottom left vertex.
so, the side x corresponds to the side x+2.
and, of course, the top side corresponds to the bottom side.
going from the small to the large triangle the scaling factor is 6/2 = 3/1 = 3.
therefore
3 × x = x + 2
3x = x + 2
2x = 2
x = 1