PDA

View Full Version : Finding xyz coords of....


Sikz
Nov23-03, 02:55 AM
Given: ABC is an isosceles triangle; AB=BC; A(x,y,z); B(x',y',z'); m<ABC=m

I need, based on this information, a way to get the xyz coordinates of C. It's for a computer program I'm writing, and I'm afraid I'm rather unknowlegable about how to solve this type of problem- could someone please give me (an) equation(s) for this? The way those equation(s) work would be appreciated as well, but the equation(s) by themselves are all I really NEED.

Thank you very much.

Integral
Nov23-03, 12:34 PM
Unfortunately, given that you have expressed this in 3d space you will not be able to find a unique point which completes your triangle. There will be infinitely many triangles, each laying in a different plane.

I am not sure what your constriction
m<ABC=m

means, could you elaborate on that?

Sikz
Nov23-03, 08:49 PM
Ah yes, such a silly mistake. I assumed I would need xyz coords since the program deals with 3d space, but the triangle is on a plane... I actually only require xy coords.

And by m<ABC=m I meant "measure of angle ABC = m". Since I am unaware of the way to type a proper angle symbol, I used < :P.

Hurkyl
Nov24-03, 06:21 AM
Well, if angle B has measure m, then the other two angles have measure 90-m/2. Does that help?

(Also, B must lie on the perpendicular bisector of AC)