When a cylinder is placed on a fluid, it is partially submerged and attains equilibrium at that state.
In equilibrium, $$F_B=mg$$ where $F_B$ is the buoyant force and $mg$ is the weight of the cylinder.
But we know that $F_B=m_{\text{liquid displaced}}\ g$. Thus, $ m_{\text{liquid displaced}}\ g=mg$
But in the above case, $m_{\text{liquid displaced}}\neq m$ as only a part of $m$ is inside the fluid.
During partial submersion, how can we write the equation for equilibrium state?