Hello helpmeplease,
For this problem, you would use the tangent of 30 degrees. (it is the trig function of opposite/adjacent.)
It helps to first draw out the triangle, which would look something like:
(pretend the nest is at the top of the tree)
You know the angle is 30 deg, and the height is 6. So:
tan(30) = opp/adj
tan(30) = 6/x
Multiply both sides by x.
* tan(30) = 6
Divide both sides by tan(30).
x = 6/ tan(30)
$${\frac{{\mathtt{6}}}{\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}{\left({\mathtt{30}}^\circ\right)}}} = {\mathtt{10.392\: \!304\: \!845\: \!406\: \!527\: \!5}}$$
So the horizontal distance from the nest to you would be about 10.4 meters:)