SOLUTION: I would like to know how to get the angle, while I know three points in three dimensional space. Point A is (0,0,0), point B is (x,y,z), and point C (x', y',z'). I want to get the

Algebra ->  Formulas -> SOLUTION: I would like to know how to get the angle, while I know three points in three dimensional space. Point A is (0,0,0), point B is (x,y,z), and point C (x', y',z'). I want to get the       Log On


   

Question 98718: I would like to know how to get the angle, while I know three points in three dimensional space. Point A is (0,0,0), point B is (x,y,z), and point C (x', y',z'). I want to get the angle at A. I need the equation to get the angle. Thank you very much...
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
the easiest way to get the angle is to use the Law of Cosines

all you need is the length of the 3 sides, which you can find with the distance formula

cosA=((AB)^2+(AC)^2-(BC)^2)/(2(AB)(AC))