Answer:
2 seconds
Step-by-step explanation:

Step-by-step explanation:

Let 
Then 
or

This gives us
or all integer multiples of 
It should be 5/13 because the opposite angle from D is 12, which you would use if you are looking for sine. But, since you are looking for cosine, it is adjacent over hypotenuse. Therefore leaving you with 5/13, since your hypotenuse is always your longest side and the adjacent is the other side from the one opposite of the angle.
Answer:
<h2>
11.4</h2>
Solution,
∆ ACB = ∆ EFD
finding the value of X,

Apply cross product property

Calculate the product

Divide both sides by 5

Calculate

Hope this helps...
Good luck on your assignment...