Through what angle does the observer see the pole?

Question

My professor claims that it's best to use law of sin or cosine.

 

One end of a 9.3 foot pole is 13.6 feet from an observer's eyes, and the other end is 17.4 feet from the observer's eyes.  Through what angle does the observer see the pole?

Answer 1

Hi, Kayla.

 

The Law of Cosines should be used when you are given all 3 sides of a triangle (each length given forms one side of a triangle).

 

2ab cos(alpha) = a^2 + b^2 - c^2

 

where a = distance to one end, b = distance to other end, and c = length of pole

 

Just rearrange to solve for alpha and plug in.

 

If you need more help on this or similar problems please contact me.

 

Bob K