Answer:
x = 2
Explanation:
You can split this triangle up into 2 right triangles. The bottom of one of the triangles is 4 since 8/2 = 4. Next, use the pythagorean theorem to find x.
a^2 + b^2 = c^2
4^2 + x^2 = (square root 20)^2
16 + x^2 = 20
x^2 = 4
x = 2
Hope this helps