Answer: 12.20 feet.
Step-by-step explanation:
Observe in the figure attached that a right triangle is formed.
Then, you need to remember the identity:
[tex]cos\alpha=\frac{adjacent}{hypotenuse}[/tex]
In this case you can identify that:
[tex]adjacent=10\\hypotenuse=x[/tex]
[tex]\alpha=35\°[/tex]
Then, to find the length of the wooden board (x), you need to substitute values and solve for x.
Therefore, you get:
[tex]cos(35\°)=\frac{10}{x}\\\\(x)(cos(35\°))=10\\\\x=\frac{10}{cos(35\°)}\\\\x=12.20[/tex]
The length of the wooden board is: 12.20 feet.