def ro(formation_factor, rw):
    """
    Archie Ro - Resistivity of water saturation formation (ohm.m)

    Parameters
    ----------
    formation_factor : float
        Archie Formation Factor
    rw : float
        Resistivity of formation water (ohm.m)

    Returns
    -------
    float
        Returns resistivity of water saturation formation (ohm.m)
    """
    return formation_factor * rw