Solució: \begin{align} R_e &= \cssId{Step1}{ \frac {U^2}{P_1}}\\[3px] &\cssId{Step2}{Re = 75,57 } \\[3px] &\cssId{Step3}{R_m= \frac{U^2}{P_2}-R_e = 127,9 } \\[3px] \end{align}