Which set of values could be the side lengths of a 30-60-90 triangle?

Let us take 4,,8

Step-by-step explanation:

When you have a 30-60-90 triangle, your sides will always have a set pattern. 

The side across from the 30 angle will be equal to n (so n = 4).

The side across from the 60 angle will always be equal to n√(3) (so  4√(3)).

The side across from the 90 angle will always be 2n (so, 8).

You could go into trig or Pythagorean theorem to prove this, but it's much simpler to remember it because it's a special triangle.