v2 = {x2 - xA, y2 - yA}
xp = v1.x * v2.y - v1.y * v2.x
if xp > 0:
    print('on one side')
elif xp < 0:
    print('on the other')
else:
    print('on the same line!')
How can I check if a point is below a line or not?