Angle calculation

Question

I m having three atoms (a,b,c) with 9 coordinates
in which I calculated the distance for a and c, b and c and got results in Armstrong
Noww I want to find angle between a and b in degree How ??

Answer 1

First calculate the height of the triangle. You get a right triangle. Use the formulas of angle in a right triangle.

Answer 2

I don't understand the question. Can you show us the code or some of your progress?

Answer 3

If you mean the angles in a triangle, when you have coordinates for each corner, you can use the angle between two lines formula (and gradient formulas).
https://www.math-only-math.com/angle-between-two-straight-lines.html
If the maths is difficult, ask me to explain. For me to help though, you really should share your code.

Answer 4

x1=13.380
y1=17.835
z1=32.697
x2=14.166
y2=18.076
z2=33.485
x3=14.638
y3=19.021
z3=34.997
a=((x3-x1)**2+(y3-y1)**2+(z3-z1)**2)**0.5
b=((x3-x2)**2+(y3-y2)**2+(z3-z2)**2)**0.5
after this I want to calculate angle ??

Answer 5

Try this website. You need to combine the second "Example" (red writing) and the "Angle between lines" (blue writing).
http://www.nabla.hr/PC-LinePlaneIn3DSp2.htm
The maths is clearly quite difficult. You might need to tweak some of the formulas to transfer them into code. I might try for you later if I have time.

Answer 6

Or you could attempt recreate the triangle in 2D, then use the easier 2D formulas.

Answer 7

In Python, for the angle at (x2, y2, z2)...
import math
a1 = x2 - x1
b1 = y2 - y1
c1 = z2 - z1
a2 = x3 - x2
b2 = y3 - y2
c2 = z3 - z2
radians = math.acos( (a1*a2 + b1*b2 + c1*c2) * (a1**2 + b1**2 + c1**2)**(-0.5) * (a2**2 + b2**2 + c2**2)**(-0.5) )
degrees = radians / math.pi * 180
Hopefully works...

Answer 8

https://code.sololearn.com/cK3lc3Q1ERlc/?ref=app

Answer 9

Need help for the other two angles?