Angle
lastmod 2023-01-07created 2022-12-216 edits
In geometry, an angle is the figure formed by two rays sharing a common endpoint. This endpoint is called the vertex of the angle, and the two rays are called the sides of the angle. The quantity expressing how far apart the two sides of an angle are, that is, the size of the angle, is called the angle measure. Strictly speaking, it is the extent of counterclockwise opening from the initial side to the terminal side. An angle usually means one defined on a plane, but a solid angle in three-dimensional space can also be defined.
How to find the angle between two lines
Theory
Find_the_Angle_between_three_points.png
Python
# -*- coding: utf-8 -*-
import math
from typing import NamedTuple
class Point(NamedTuple):
x: int
y: int
def angle(a: Point, b: Point, c: Point) -> float:
ang = math.degrees(math.atan2(c[1]-b[1], c[0]-b[0]) - math.atan2(a[1]-b[1], a[0]-b[0]))
return ang + 360 if ang < 0 else ang
Using Numpy Library
import numpy as np
a = np.array([6,0])
b = np.array([0,0])
c = np.array([0,6])
ba = a - b
bc = c - b
cosine_angle = np.dot(ba, bc) / (np.linalg.norm(ba) * np.linalg.norm(bc))
angle = np.arccos(cosine_angle)
print np.degrees(angle)