Calculate vertical distance.

    :param inc: (float) inclination angle in degrees
    :param sd:  (float) slope distance in any units

def vd(inc, sd):
    """
    Calculate vertical distance.

    :param inc: (float) inclination angle in degrees
    :param sd:  (float) slope distance in any units
    """
    return abs(sd * math.sin(math.radians(inc)))