2.0*10^-9=(6.67^10-11)(7.1)(7.7)/R^2 Solve for R?

$${\mathtt{2}}{\mathtt{\,\times\,}}{{\mathtt{10}}}^{-{\mathtt{9}}} = {\frac{\left({{\mathtt{6.67}}}^{{\mathtt{10}}}{\mathtt{\,-\,}}{\mathtt{11}}\right){\mathtt{\,\times\,}}{\mathtt{7.1}}{\mathtt{\,\times\,}}{\mathtt{7.7}}}{{{\mathtt{R}}}^{{\mathtt{2}}}}} \Rightarrow \left\{ \begin{array}{l}\end{array} \right\}$$

$${{\mathtt{R}}}^{{\mathtt{2}}} = {\frac{\left({{\mathtt{6.67}}}^{{\mathtt{10}}}{\mathtt{\,-\,}}{\mathtt{11}}\right){\mathtt{\,\times\,}}{\mathtt{7.1}}{\mathtt{\,\times\,}}{\mathtt{7.7}}}{\left({\mathtt{2}}{\mathtt{\,\times\,}}{{\mathtt{10}}}^{-{\mathtt{9}}}\right)}} \Rightarrow \left\{ \begin{array}{l}\end{array} \right\}$$

you can finish it on you hand calculator.