The height of the triangle is an altitude to the base of the triangle which splits the original triangle into two equal triangles that are 30-60-90 right triangles.
In either triangle the altitude of 8sqrt3 is opposite the 60 degree angle and the side opposite to the 30 degree angle is the base of the right triangle and equal to 8.
Since the base of the right triangle is half of the original triangle, so the length of the side of the original triangle is 16.
Susan R.
Thank you so much!04/11/21