Helloooo ...


Can someone kindly direct me ...

I have 3 points in an x,y,z plane. and I would like to calculate (in degrees) the angle between the 2 lines formed by these.

Example:

point A: 3,5,7
point B: 5,6,1
point C: 9,9,4

how can i measure the angle between A-B (line) and B-C (line)?

or in other words, how to implement calculating angles between vectors in 3-D coordinates in excel?

Thank you