m = \frac{A_{k o g u}}{r}, A_{k o g u} = \frac{A_{k a s u}}{η}, A_{k a s u} = \frac{N s}{v}

${m=\frac{A_{kogu}}{r},\quad A_{kogu}=\frac{A_{kasu}}{\eta},\quad A_{kasu}=\frac{Ns}{v}}$