Here, we want to get the value of r
We can get it by cross-multiplication
We have this done as follows;
[tex]\begin{gathered} \frac{r}{6.2}\text{ = }\frac{13}{2} \\ \\ 2\times\text{ r = 13}\times6.2 \\ r\text{ = }\frac{13\times6.2}{2} \\ r\text{ = 40.3} \end{gathered}[/tex]