  Starting from a recently proposed comprehensive theory for the high-Tc
superconductivity in cuprates, we derive a general analytic expression for the
planar resistivity, in the presence of an applied external magnetic field
$\textbf{H}$ and explore its consequences in the different phases of these
materials. As an initial probe of our result, we show it compares very well
with experimental data for the resistivity of LSCO at different values of the
applied field. We also apply our result to Bi2201 and show that the
magnetoresistivity in the strange metal phase of this material, exhibits the
$H^2$ to $H$ crossover, as we move from the weak to the strong field regime.
Yet, despite of that, the magnetoresistivity does not present a quadrature
scaling. Remarkably, the resistivity H-field derivative does scale as a
function of $\frac{H}{T}$, in complete agreement with recent magneto-transport
measurements made in the strange metal phase of cuprates \cite{Hussey2020}. We,
finally, address the issue of the $T$-power-law dependence of the resistivity
of overdoped cuprates and compare our results with experimental data for
Tl2201. We show that this provides a simple method to determine whether the
quantum critical point associated to the pseudogap temperature $T^*(x)$ belongs
to the SC dome or not.
