Results 1 to 3 of 3

Math Help - 3rd Point of A Triangle

  1. #1
    Newbie
    Joined
    Jan 2011
    Posts
    2

    3rd Point of A Triangle

    First off I'm not entirely sure this is a trig question. If it's in the wrong place could a moderator maybe move it? Using trig was just my inital thought on how to solve this problem but I could be extremely wrong.

    3rd Point of A Triangle-math.jpg

    So I'm a programmer and I'm working in 3D space. This is the problem I need to solve.

    I have the points of A and B. I also have access to all the distances of all three sides of the triangle. All I need to do is find C. Basically I want the point perpindular to AB, that is a fixed distance away, directly above (or below) C. I feel like I'm missing something really simple but I just can't figure out what.

    This would be a fairly simple problem to solve with some graph paper and a ruler but because this is for a computer program I need it to be in the form of some sort of equation that it will understand. It also needs to work for different values of A and B.

    Thanks for any help. As I said please move this topic if I'm in the completely wrong area.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Jan 2011
    Posts
    15
    Quote Originally Posted by Silverlode View Post
    First off I'm not entirely sure this is a trig question. If it's in the wrong place could a moderator maybe move it? Using trig was just my inital thought on how to solve this problem but I could be extremely wrong.

    Click image for larger version. 

Name:	math.jpg 
Views:	47 
Size:	88.1 KB 
ID:	20504

    So I'm a programmer and I'm working in 3D space. This is the problem I need to solve.

    I have the points of A and B. I also have access to all the distances of all three sides of the triangle. All I need to do is find C. Basically I want the point perpindular to AB, that is a fixed distance away, directly above (or below) C. I feel like I'm missing something really simple but I just can't figure out what.

    This would be a fairly simple problem to solve with some graph paper and a ruler but because this is for a computer program I need it to be in the form of some sort of equation that it will understand. It also needs to work for different values of A and B.

    Thanks for any help. As I said please move this topic if I'm in the completely wrong area.
    You can build an equation system and solve it for XA, YA, YZ:

    I: (XA-XB)+(YA-YB)+(ZA-ZB)=|AB|
    II: (XA-XC)+(YA-YC)+(ZA-ZC)=|AC|
    Pythagoras: III: (XA-XB)+(YA-YB)+(ZA-ZB)=[(XA-XC)+(YA-YC)+(ZA-ZC)]+|BC|

    PS: I believe you are going to obtain more than one unique point for A because you have a 3D coordinates system.
    Last edited by ahaok; January 19th 2011 at 12:21 PM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jan 2011
    Posts
    2
    Thanks for the answer. It seems like your answer would work on paper however it it may be quite difficult for coding purposes. Hopefully it proves useful for someone else.

    I actually came up with a better and easier to code approach in the last few hours for what I wanted to achieve. I ended up ditching the whole triangle concept altogether. Thanks very much anyway though.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Coordinate of a point in a triangle
    Posted in the Geometry Forum
    Replies: 4
    Last Post: January 27th 2011, 03:10 PM
  2. A point within an equilateral triangle
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: December 7th 2010, 02:48 AM
  3. Point in triangle...
    Posted in the Geometry Forum
    Replies: 6
    Last Post: July 26th 2010, 10:33 PM
  4. Replies: 1
    Last Post: June 18th 2008, 06:17 AM
  5. height of point on a triangle
    Posted in the Calculus Forum
    Replies: 0
    Last Post: September 18th 2007, 08:30 AM

Search Tags


/mathhelpforum @mathhelpforum