This is a 30, 60, 90 triangle. One angle measures 30° and the other measures 90°. The other has to be 60° because all triangles are 180°. These triangles have special rules:
Say the side opposite 30° (in this case, y) is equal to 1
The side opposite the 60° (in this case, x) is equal to √3
The side opposite 90° is 2.
If 16√3 is opposite 90°, then opposite 30° would be half of that. Therefore, y = 8√3.
Now we need to multiply y by √3 to get x, because the side opposite 60° is always that of 30° multiplied by √3.
8√3 * √3 = 24 as the √3s cancel and become 3. So 8 multiplied by 3 makes 24.
Therefore, x = 24.