  We show that simultaneous precision measurement of the CP-violating phase in
time-dependent Bs --> J/psi phi study and the Bs --> mu+ mu- rate, together
with measuring m_t' by direct search at the LHC, would determine
V_{t's}^*V_{t'b} and therefore the b --> s quadrangle in the four-generation
standard model. The forward-backward asymmetry in B --> K* l+ l- provides
further discrimination.
