Answer:
7.9km
Step-by-step explanation:
(a)See attached for the diagram representing this situation.
(b)
In Triangle ABC

Next, we determine the value of Angle B.

Finally, we find b.

The distance between the small plane and the observation tower is 7.9km.
Consider the following table.
Answer:
f=ab/a+b
Step-by-step explanation:
Let's solve for f.
1/f=1/a+1/b
Your answer is C 108.5 !!!!!!!!!