find angle between lines

hello

i need to find the angles between lines

how can i do in code

[John D'Errico]

As a hint:

http://mathworld.wolfram.com/LawofCosines.html

That will suffice. Why not try it?

Or, you could find the inclination of each line, best done using atan2. Then subtract. That too will work, as long as you are careful.

https://www.mathstopia.net/coordinate-geometry/angle-two-lines

Answer 1

[madhan ravi]

https://www.mathworks.com/matlabcentral/answers/78195-how-to-measure-angle-between-the-lines#answer_87898

[OriAlpha]

hello,

can you tell me in terms of my points the same formule

[OriAlpha]

i have 3 points its formulated for 4 points

[madhan ravi]

one point is common for both the lines

[OriAlpha]

dont get me wrong can u formulate for 3 points

[madhan ravi]

x = [800 905]; % common point
y = [250 330];
a = [800 905]; % common point
b = [825 333];
angle_between = (atan((y(2)-y(1))/(x(2)-x(1)))...
    - atan((b(2)-b(1))/(a(2)-a(1)))) * 180/pi   % in degrees