weighed means determine weight, which is meaningless in that context, as the earth is not in a uniform gravitational field, except that of the sun, which is countered by the earth's movement in its orbit.
I think you mean mass. see reference below.
The mass of the Earth may be determined using Newton's law of gravitation. It is given as the force (F), which is equal to the Gravitational constant multiplied by the mass of the planet and the mass of the object, divided by the square of the radius of the planet. We set this equal to the fundamental equation, force (F) equals mass (m) multiplied by acceleration (a). We know that the acceleration due to gravity is equal to 9.8 m/s², the Gravitational constant (G) is 6.673 × 10^−11 Nm²/kg², the radius of the Earth is 6.37 × 10^6 m, and mass cancels out. When we rearrange the equation and plug all the numbers in, we find that the mass of the Earth is 5.96 × 10^24 kg.
F = Gm1m2/r² = ma
Gm/r² = g
m = gr²/G
m = (9.8 m/s²)(6.37 × 10^6 m)2/(6.673 × 10^−11 Nm²/kg²)
m = 5.96 × 10^24 kg