Suppose we have a series circuit with three resistors and a source voltage of $15$ volts. If the first two resistor values are R$1=1$ k$$ and R$2=8\mathrm{.}1$ k$,$ solve for R$3$ in terms of all the other variables. What is the necessary resistance value of R$3$ to obtain a $0\mathrm{.}2$ volt drop across resistor R$1?$