Answer:
x = 60°
Step-by-step explanation:
using the cosine ratio in the right triangle
cos x = [tex]\frac{adjacent}{hypotenuse}[/tex] = [tex]\frac{9}{18}[/tex] = [tex]\frac{1}{2}[/tex] , then
x = [tex]cos^{-1}[/tex] ([tex]\frac{1}{2}[/tex] ) = 60°
