Answer: [tex]\bold{b.\ \dfrac{x}{12}}[/tex]
Step-by-step explanation:
[tex]cos\ \theta=\dfrac{adjacent}{hypotenuse}\\\\\\\text{The side adjacent (touching) the }70^o\text{ has a length of x.}\\\text{The hypotenuse (opposite of "not touching" the }90^o\text{ angle) has a length of 12.4}\\\\\\cos\ 70^o=\dfrac{x}{12.4}[/tex]
