Remember that the triangle is given two angles one is 90 degrees and theme other is 60 degrees. All triangles equal 180 degrees so you can add up 60+90= 150 180-150= 30 degrees
Now we know the unknown angle is 30 degrees, so the side with the length 8 is across from the 30 degree angle. All sides across from 30 degree angles are half the hypotenuse. Since the unknown side is across from the 90 degree angle it is a hypotenuse. Therefore 8 is half the unknown side so x=16
