Finding Angle between 2 points

Hello,

I need to calculate the angle between two point from the matlab plot. I tried by applyingthe code which is provided in the discussion but the result is not correct.

The image is attached, I want to find the angle theta which is fromed by point p1,p2 and o.

P1,P2 coordinates are known to us.

I tried using the code provided in the link attached below but the answer is not correct.

https://in.mathworks.com/matlabcentral/answers/109797-find-angle-between-dots

I need your help regarding the same.

Thanks in Advance.

Awaiting for response.

[MaryD]

Do you know the coordinates of O point ? Or anything about that ?

[aaditya chandel]

yes the point O coordinates are known.

Answer 1

[Gifari Zulkarnaen]

Is this what you mean?

P1 = [10  210];
P2 = [140 210];
Z0 = [(P1(1)+P2(1))/2 225]; % Reference point, assuming it is in the middle of P1 & P2

degree = 2*atand((P2(1)-Z0(1))/(Z0(2)-P2(2)));

[aaditya chandel]

The coordinate of Z0 is known.

[aaditya chandel]

As shown in the figure P1,P2 and O point coordinates are know.

[aaditya chandel]

For this case Z0 appears to be in the middle but it might not be true in other cases.

But its possible to obtain the coordiante.

Answer 2

[MaryD]

r1=sqrt((x1-xo).^2+(y1-yo).^2);

r2=sqrt((x2-xo).^2+(y2-yo).^2);

alpha=acos((x1-xo)/r1);

beta=acos((x2-xo)/r2);

theta=alpha-beta;

keep in mind that acos is specified for pi <0:pi> so if one (or both) points would be placed under O point you have to adjust this equation.

[aaditya chandel]

Thanks.