Guywire, finding height of the powerpole

Hello, thank you to anyone looking at this problem. I recently took a career changing test and did not pass. One problem I'd like to be prepared for next time involves a guywire connected to the top of two poles. 

I truly hope I'm remembering this problem exactly as it appeared. Initially, someone thought it as a catenary curve, it isn't as the test doesn't allow anyone to use a calculator. 

problem: A 20ft guywire is attached to the top of two poles. If the bottom of the guywire is 12ft from the ground, how tall are the poles? 

Updated :  a 20ft guywire is hanging between two poles. The distance between these poles is 8ft. If the guy wire reaches a distance of 12ft from the ground, how tall are the poles ?


  • Aman R Aman R

    Question is tricky and incomplete! Please mention guywire is hanging or straight. If it's hanging then catenary equations are applied if it's straight then geometry can be applied with few more parameters provided.

  • Aman R Aman R

    Please upload full question with diagram if there any ?

  • So there isn’t a picture for this problem on the test. The cable is hanging, but it isn’t a catenary curve has the test is super basic for most people. It is tricky, but “answer not shown” is not an option on the answer key.

  • I do appreciate the answer. Is there any other way to possibly solve this problem? Just making sure when it comes to the test, it doesn’t mess with me as it did last time

  • I updated the question, this is all I can recall from it.

  • Aman R Aman R

    If it's hanging then hyperbolic equation must be used. Other possibility would be when the cable is straight and inclined, so one pole length will be simply 12ft and other will be 12 plus some more height which can be obtained using Pythagoras using your assumption of 8 ft separation. However in catenary part the distance between them is not required. Hence the question was correct and it must be hanging. And both poles are of same height.


Answers can only be viewed under the following conditions:
  1. The questioner was satisfied with and accepted the answer, or
  2. The answer was evaluated as being 100% correct by the judge.
View the answer

1 Attachment

The answer is accepted.
Join Matchmaticians Affiliate Marketing Program to earn up to a 50% commission on every question that your affiliated users ask or answer.