calculate an angle and distance from three points

hi...How to calculate an angle and distance from three points? ex P1 = (x=2, y=50) P2 = (x=9, y=40) P3 = (x=5, y=20)

[Marta Salas]

You can not define an angle and a distance between 3 points. Do you mean by pairs of those 3 points?

Answer 1

[Roger Stafford]

I'll show you how to find one of the angles in the triangle P1 = [x1;y1], P2 = [x2;y2], P3 = [x3;y3]. The inner angle at vertex P1 is given by:

 A1 = atan2(abs((x2-x1)*(y3-y1)-(x3-x1)*(y2-y1)), ...
                (x2-x1)*(x3-x1)+(y2-y1)*(y3-y1));

As for the "distance", please tell us what kind of distance you have in mind. Distance from what to what?

[bil bbil]

first of all thank you very much. I'm looking for the distance between P1,P2 and P1,P3 for then stored in an array

[Mansour Attaallah]

Thank you very much it is really helpful

Answer 2

[Marta Salas]

The distance can be calculated as the norm of the vector between two points:

P1 = [2; 50], P2 = [9; 40], P3 = [5; 20]
d1 = norm(P2-P1); 
d2 = norm(P3-P1); 

distances =[d1; d2]

[bil bbil]

thank you ^^