Solve R_{p}=0,366*frac{rho_{c}}{1}*(lg2l/d+0,5lg4t+1/4t-1)

$$R _ { p } = 0,366 \cdot \frac { \rho _ { c } } { 1 } \cdot ( \lg \frac { 2 l } { d } + 0,5 \lg \frac { 4 t + 1 } { 4 t - 1 } )$$

Solve for R_p

$$R_{p}=\frac{183\log(e)\left(\ln(\frac{4t+1}{4t-1})+2\ln(\frac{l}{d})+2\ln(2)\right)\rho _{c}}{1000}$$

$$\left(l>0\text{ and }d>0\text{ and }|t|>\frac{1}{4}\right)\text{ or }\left(l<0\text{ and }d<0\text{ and }|t|>\frac{1}{4}\right)$$

Solve for d

$$\left\{\begin{matrix}d=2\sqrt{\frac{4t+1}{4t-1}}l\times 10^{-\frac{500R_{p}}{183\rho _{c}}}\text{, }&l\neq 0\text{ and }\rho _{c}\neq 0\text{ and }|t|>\frac{1}{4}\\d>0\text{, }&l>0\text{ and }R_{p}=0\text{ and }\rho _{c}=0\text{ and }|t|>\frac{1}{4}\\d<0\text{, }&l<0\text{ and }R_{p}=0\text{ and }\rho _{c}=0\text{ and }|t|>\frac{1}{4}\end{matrix}\right.$$