Mass of the earth can be determined by the equation

We know that the acceleration due to gravity is given as:

$g=\frac{GM}{R^2}$
By rearranging the terms, we will get,
$M=\frac{R^{2}g}{G}$
Hence the mass of the earth can be determined by:

${\mathrm{M}}_{\mathrm{e}}=\frac{{{\mathrm{R}}^2}_{\mathrm{e}}.\mathrm{g}}{\mathrm{G}}$
Since we know the value of the radius of the earth, gravitational constant and can calculate the acceleration due to gravity on the earth easily, we can use this equation to determine the mass of the earth.