Is it possible to have a cosine of 1.0000 I was given a triangle:
side opposite of angle A: unknown, referred to as L
side adjacent of angle A: 11'
hypotenuse: 14'
I have to find the cosine of angle A, the degrees, and the length of "L", opposite angle A, in feet.  
L is equal to 8.6602, which in feet is 8'-7 7/16. I did the math, and got angle A= 38 degrees 
(my instructor wants length in feet-inches-fraction, I'm in pipefitters school. He also doesn't want minutes or seconds for the angles)
However, when I did the cosine function, I ended up with .999905 
We are supposed to round decimals to the fourth place. However, that leaves me with 
.9999
which should round up to 
1
But...what I'm wondering is can I even have a whole number for a cosine, or should I leave it at .9999?
If .9999 is the mathematically correct answer, I need to know why, in order to defend it in class. If 1 is the correct answer, then I'd just like to know why. However, I asked Google and haven't been able to get an answer that I understand.

You found the cosine of $11/14$ degrees.  But you needed the arccosine (not the cosine) of $11/14$.  Just $11/14$, not $11/14$ degrees.  The calculator in front of me gives
$$
\cos^{-1} \frac{11}{14} \approx 38.2^\circ.
$$
The cosine of $11/14$ degrees is about $0.9999059$, but that's not what you need here.
