In the circuit shown below, the elevation sensor generates a voltage $(v_s)$ as a function of the height above sea level $(h)$ given by the equation:

$v_s=2+0\mathrm{.}2h$

where $h$ is in Km $.$

$($a$)$ Find the value of $R_x$ such that output voltage $v_{{?}_{?}}(o)$ in Volts is an exact indicator of the height $h$ in Km $,$ i$.$e$.,"v_o=h".(10$ pts