1. Limited time only! Sign up for a free 30min personal 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!

Trig/geometry help (triangles/finding sides)

  1. Dec 17, 2012 #1
    1. The problem statement, all variables and given/known data
    h83RV.png
    Find side 'R'. L = 6.10 meters, theta = 36.9 degrees, and phi = 53.1 degrees.

    2. Relevant equations
    Pythagorean Theorem
    Similar triangles
    Law of Sines
    Law of Cosines

    3. The attempt at a solution
    I don't see any way I can attempt this, I'm very rusty with my trig. We have a known side and a right angle, but I don't see how I can make any other angles (since we only have one side I'm assuming I need to get an angle somewhere
     
  2. jcsd
  3. Dec 17, 2012 #2

    Mentallic

    User Avatar
    Homework Helper

    Draw a vertical line through the right side of the length L (the point on the triangle). The length L will be perpendicular to this line, yes? And now take notice that [itex]\phi[/itex] would be the angle between the vertical and the side of the triangle because of the parallel lines rule (the wall is parallel to the vertical line we constructed).
     
  4. Dec 17, 2012 #3

    lurflurf

    User Avatar
    Homework Helper

    law of sines gives

    L/sin(phi+theta)=R/cos(phi)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Trig/geometry help (triangles/finding sides)
Loading...