If universal gravitation constant G = 6.67 x 10-11 Nm2 kg-2;
The radius of the earth R = 6.4 x 106 m and acceleration due to gravity on the surface of the earth g = 10 ms-2, the mass of the earth in kilograms must be nearly:
1
6 × 1022
2
9 × 1022
3
6 × 1024
4
9 × 1024