import math
AX = 0
AY = 0
BX = 100
BY = 0
abx = AX - BX
aby = AY - BY
minangle = 100
minindex = -1
pts = [[50, -10],[50, -20],[50, 1],[50, 20]]
for i, p in enumerate(pts):
pbx = p[0] - BX
pby = p[1] - BY
angle = math.atan2(-pbx*aby+pby*abx, pbx*abx+pby*aby)
if angle < 0:
angle += 2*math.pi
if angle < minangle:
minangle = angle
minindex = i
print(pts[minindex])# your code goes here
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