
Algebra PreAlgebra and Basic Algebra Math Forum 
 LinkBack  Thread Tools  Display Modes 
January 20th, 2010, 01:03 AM  #1 
Newbie Joined: Jan 2010 Posts: 4 Thanks: 0  Finding distance using two angles of elevation
A question in my trigonometry book has bugged me for the longest time. A Chapter 1 level2 application reads like this: "In the movie Close Encounters of the Third Kind, there was a scene in which the star, Richard Dreyfuss, was approaching Devil's Tower in Wyoming. He could have determined his distance from Devil's Tower by first stopping at a point P and estimating the angle P. After moving 1.000 x 10^2 m toward Devil's Tower, he could have estimated the angle N, as shown in the figure. How far away from Devil's Tower is point N?" So, basically the first angle of elevation is 13.5 degrees and after moving 100 m in the direction toward Devil's Tower the angle of elevation is 14.8 degrees. What I want to know is how this can be done without advanced techniques in trigonometry. This is in the first chapter of the book and no advanced technique are explained as of yet. Basically, what has been explained thus far in the book in the trigonometric functions, their inverses, and the use of similar triangles to find similar angles and side measures. I would like to know the simplest method that could be used to determine the distance. Thank you in advanced. 
January 20th, 2010, 03:24 AM  #2 
Senior Member Joined: Feb 2009 From: Adelaide, Australia Posts: 1,519 Thanks: 1  Re: Finding distance using two angles of elevation
[attachment=0:3bame9tc]elev.GIF[/attachment:3bame9tc] By the definition of tan, you have: But you don't know the value of y. Can you still find x? Yes, if you divide one by the other: Subtract 1 from both sides, make the lefthand side one fraction, invert both sides and multiply by 100 to get: 
January 20th, 2010, 09:00 PM  #3 
Newbie Joined: Jan 2010 Posts: 4 Thanks: 0  Re: Finding distance using two angles of elevation
@aswoods Thank you so much for the quick reply. I can easily see how this works out thanks to your explanation. It is basically using the proportionality of the tangent of the angles to the distances and the height. Would that be a good explanation in word form (just to go a bit further )?


Tags 
angles, distance, elevation, finding 
Search tags for this page 
finding distance using angle of elevation,find distance using angle of elevation,Simplest method of finding angle of elevation,angle of elrvation find the dustance maths,angle of elevation and distance,how to find angle of elevation,Angles of elevation book 2
Click on a term to search for related topics.

Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Finding angles within a box  Tooperoo  Algebra  1  August 1st, 2013 01:57 PM 
finding angles  ilovetheflowguy  Algebra  1  November 26th, 2011 11:10 PM 
Angles of Elevation & Depression  Heartsdomain  Algebra  1  April 20th, 2008 10:25 PM 
Angles of Elevation & Depression  Heartsdomain  Algebra  2  April 20th, 2008 08:16 PM 
Finding Angles  symmetry  Algebra  2  August 21st, 2007 06:22 PM 