Answer:
x ≈ 20
Step-by-step explanation:
Using the cosine ratio in the right triangle
cos26° = [tex]\frac{adjacent}{hypotenuse}[/tex] = [tex]\frac{18}{x}[/tex] ( multiply both sides by x )
x × cos26° = 18 ( divide both sides by cos26° )
x = [tex]\frac{18}{cos26}[/tex] ≈ 20.0 ( to the nearest tenth )