1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Angle Ratios

  1. Apr 1, 2008 #1
    1. The problem statement, all variables and given/known data

    Tree A is 10 m tall. Tree B is 60 m tall. You're standing on level ground at a position that is 25 m from tree A and 75 m from tree B. You're eye height is 1.5 m above the ground. Find the ratio of theta B/ theta A, of the angles (measured from the horizontal) at which you must look to view the top of each tree.



    2. Relevant equations

    tan(theta) tan -1 (theta)



    3. The attempt at a solution

    I think I have found both angles A and B: A = 18.8 degrees B = 37.95 degrees

    This is absolutely crazy that I don't know how to find the B/A ratio! do I just put 37.95/18.8? Or do I need to divide both of them by 90 first, since the overall angle is a horizontal?

    Thanks in advance.
     
    Last edited: Apr 1, 2008
  2. jcsd
  3. Apr 1, 2008 #2

    dlgoff

    User Avatar
    Science Advisor
    Gold Member

    "B/A ratio"

    It's just as you have shown B divided by A. i.e. 37.95/18.8 (note I didn't check you math for these angles)
     
  4. Apr 1, 2008 #3
    thank you! do these angles sound reasonable?
     
  5. Apr 1, 2008 #4

    dlgoff

    User Avatar
    Science Advisor
    Gold Member

    How did you get these angles? What is the relation between the height of the tree, the distance from the tree and the angle?
     
  6. Apr 1, 2008 #5
    With everything I knew I was able to form two triangles and in each I knew two sides. A: 8.5 and 25 and hypotenuse unknown. B: 58.5 and 75 and hypotenuse unknown. Using the tangent inverse, I found theta for each.
     
  7. Apr 1, 2008 #6

    dlgoff

    User Avatar
    Science Advisor
    Gold Member

    You got it. Good job.
     
  8. Apr 1, 2008 #7
    Thank you =]
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?