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!

PF erased my problem anyways triangle problem

  1. Oct 3, 2011 #1
    1. The problem statement, all variables and given/known data


    [PLAIN]http://img832.imageshack.us/img832/5249/unledhbk.png [Broken]



    3. The attempt at a solution

    Alright PF just erased all my work so here is my work without LaTex because I am too frustrated to do this all again

    Basically I found the vectors

    QP = <7,8,0>

    |QP| = √113 ≈ 10.630

    RP = <7,0,-5>

    QR = <0,8,-5>

    The others follow the same logic

    I have dinner now so I will write out how I got the angles.
     
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Oct 3, 2011 #2
    I don't know why, but the angle at Q is right when I used those magnitudes...
     
  4. Oct 4, 2011 #3

    Mark44

    Staff: Mentor

    I don't get this result for the angle at Q. Why do you think this is a right angle?
     
  5. Oct 4, 2011 #4
    Because it says it's right. No I am not talking "right angle - 90", I am was talking about "correct angle"

    Damn you English language
     
  6. Oct 4, 2011 #5

    Mark44

    Staff: Mentor

    OK - what's your question?
     
  7. Oct 4, 2011 #6

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Why? What do you get for angle Q?
     
  8. Oct 4, 2011 #7
    50.434 degrees as I have.

    My length for the vectors are wrong
     
  9. Oct 4, 2011 #8

    Mark44

    Staff: Mentor

    They look fine to me. Those are the values (the lengths) that I got, and they asked you to round to 3 dec. places. Sometimes these computer-graded things are brain-dead.
     
  10. Oct 4, 2011 #9

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    It asks for the exact values.

    I.e. √(113)
     
  11. Oct 4, 2011 #10
    Yeah I asked my professor about that and she has yet to respond...

    I really hate lazy professors giving people online assignments
     
  12. Oct 4, 2011 #11
    But it says to round to three decimal places

    EDIT: OH CMON!!! WHAT?? THAT'S SO MISLEADING!!!
     
  13. Oct 4, 2011 #12

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    The exact values for the lengths ... AND the angles rounded to 3 decimal paces.
     
  14. Oct 4, 2011 #13
    yeah I know, exact values =/= rounding.

    I hate these stupid online problems, they just catch on picky reading mistakes
     
  15. Oct 4, 2011 #14
    Why am I complaining to you?...sorry lOL
     
  16. Oct 4, 2011 #15

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    There really should have been better punctuation in the question.
     
  17. Oct 4, 2011 #16
    Different clauses, it should be

    "Find the exact values of the length ,and angle rounded to three decimal places"
     
  18. Oct 4, 2011 #17

    Mark44

    Staff: Mentor

    That caught me.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: PF erased my problem anyways triangle problem
  1. Triangle problem (Replies: 12)

Loading...