Ответ: R=\dfrac{\rho*l}{S}=\dfrac{\rho*l}{S}*\dfrac{l}{l}=[S*l=V]=\dfrac{\rho*l^{2}}{V}=[V =\dfrac{m}{\rho ‘} ]=\dfrac{\rho*l^{2}*\rho ‘}{m}
\\l= \sqrt{ \dfrac{R*m}{\rho *\rho ‘} }