Answer:
2
Step-by-step explanation:
Since they are similar triangles then the ratio will be the same on all sides.
You know the one side 5 is the same ratio to 5x so you multiply x to all sides of the little triangle to get the value of the equivalent side in the big one.
so the missing side x times x will equal the big size of the bigger triangle which is 4
x times x = 4 can only be 2
