def _mat10_get_bulk_rho_c(bulk, rho, c):
    """.. math:: bulk = c^2 \\rho"""
    if c is not None:
        if rho is not None:
            bulk = c ** 2.0 * rho
        elif bulk is not None:
            rho = bulk / c ** 2.0
        else:
            msg = 'c is the only field defined on the MAT10'
            raise RuntimeError(msg)
    elif bulk is not None:
        if rho is not None:
            try:
                c = (bulk / rho) ** 0.5
            except ValueError:
                msg = 'bulk=%s rho=%s c=sqrt(bulk/rho)=NA' % (bulk, rho)
                raise ValueError(msg)
        else:
            msg = 'c, bulk, and rho are all undefined on tbe MAT10'
            raise RuntimeError(msg)
    else:
        msg = 'c, bulk, and rho are all undefined on tbe MAT10'
        raise RuntimeError(msg)
    return bulk, rho, c
