import math


def subtended_angle(size, distance):
    """
    Return the subtended angle angle of a sphere with certain size and distance:
    https://en.wikipedia.org/wiki/Subtended_angle. Used to determine the size of
    the bounding box located at a certain position in the image.
    """
    angle = math.fabs(size) / math.fabs(distance)
    return math.degrees(angle)