EXPLANATION
Let's see the facts:
We can use the Law of Cosines to calculate the unknown value:
[tex]\cos \alpha\text{ = }\frac{\text{Adjacent cathetus}}{\text{Hypothenuse}}[/tex]
Replacing terms:
[tex]\cos 62\text{ = }\frac{x}{12}[/tex]
Isolating x:
[tex]x\text{ = 12}\cdot\cos 62\text{ = 6}[/tex]
Answer is x=6.
