The voltage divider formula is:
\( v_{out} = v_{in} \times \dfrac{\text{R2}}{\text{R1} + \text{R2}} \)
\( V_{in} = V_{out} \times \dfrac{R1 + R2}{R2} \)
\( R_1 = \left( \frac{{V_{in} \times R_2}}{{V_{out}}} \right) - R_2 \)
\( R_2 = \frac{{R_1 \times V_{out}}}{{V_{in} - V_{out}}} \)