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In a last post I wanted to know the 3rd point of vertex, actually I have some similar problem ....

I think I have all data.. for example...:

  1. 3 vertex cordinates in order to have the direction(gray arrow):

     v1 = (-0.117, 1.06,0.53)   v2 = (0.82, 2.06, 0.76)  v3 = (-0.63, 2.06, 0.76)

  2. distance between vertices:

    d1 =  1.125    d2 = 1.43   d3 = 1.46

  3. distance between v3 and new vertice:

     d4 = 0.8

image example

actually I know that this problem have two possible solutions

also I tried with the last equation and with some 2d equation, also I search in all thread of math stackenchage without any good result.

thanks for any help.

Diego

thanks to @Moti for help

Community
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Diego Quevedo
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  • You are not stating clearly your problem. What are the distances? Between points? Which specific points? You need to mark the points so you can clearly state the distances. I checked one distance - and it was not correct (1.038 where it seems like 1.125...). How did you derive the gray direction? – Moti Mar 12 '15 at 01:38
  • @Moti thanks for answere... I edit the picture to clarify the vertices... All distances are correct... – Diego Quevedo Mar 12 '15 at 22:17

1 Answers1

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It is not clear what you are trying to solve. You use d3 twice. Do you tey to calculate a distance?

The following diagram might help you define better your need:

enter image description here

CE is perpendicular to CB and in the same plane.

Moti
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  • thanks for image... which software do you use??.. anyway I want to know the E coordinates... do you have some ideas please? – Diego Quevedo Mar 13 '15 at 21:09
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    I am using GeoGebra. Finally you tell:) May be you could edit the question to reflect on what you are seeking. Here is the process you need to take:1. Find the equation of the line through EC in the plan created by ABC. 2. Solve for a point with distance 0.8 from C. 3. From the solutions you get select the one that has the opposite sign of A when you plug in the line equation of BC – Moti Mar 13 '15 at 21:38