Answer:
B
Step-by-step explanation:
Using the cosine ratio in the right triangle and the exact value
cos30° = [tex]\frac{\sqrt{3} }{2}[/tex] , then
cos30° = [tex]\frac{adjacent}{hypotenuse}[/tex] = [tex]\frac{x}{20}[/tex] = [tex]\frac{\sqrt{3} }{2}[/tex] ( cross- multiply )
2x = 20[tex]\sqrt{3}[/tex] ( divide both sides by 2 )
x = 10[tex]\sqrt{3}[/tex] → B
