Given that,
The camera sights the stadium at a 7 degree angle of depression. 
The altitude of the blimp i slide 300 m.
To find,
The line of sight distance from the camera to the stadium.
Solution,
If we consider a right angled triangle. Let x is its hypotenuse i.e. the line of sight distance from the camera to the stadium. Using trigonometry :

So, the line of sight is at a distance of 2461.65 m from the camera to the stadium.
 
        
             
        
        
        
Ok I recommend you start by
        
             
        
        
        
Answer:
You could just replace all the given possible values of k in the inequality and see which ones are solutions, but let's solve this in a more interesting way:
First, remember how the absolute value works:
IxI = x if x ≥ 0
IxI = -x if x ≤ 0
Then if we have something like:
IxI < B
We can rewrite this as
-B < x < B
Now let's answer the question, here we have the inequality:
I-k -2I < 18
Then we can rewrite this as:
-18 < (-k - 2) < 18
Now let's isolate k:
first, we can add 2 in the 3 parts of the inequality:
-18 + 2 < -k - 2 + 2 < 18 + 2
-16 < -k < 20
Now we can multiply all sides by -1, remember that this also changes the direction of the signs, then:
-1*-16 > -1*-k > -1*20
16 > k > -20
Then k can be any value between these two limits.
So the correct options (from the given ones) are:
k = -16
k = -8
k = 0
 
        
                    
             
        
        
        
Pi/3 is equivalent to 60 degrees, as 2pi is equal to 360 degrees. cos(60) in a triangle yields 1/2, and sin(60) yields (3^(1/2))/2. Thus, -pi/3, or -60 degrees would be a fourth quadrant point on the unit circle and these values would be negative as well, at cos(-pi/3)=-1/2 and sin(-pi/3)=-(3^(1/2))/2