Basic Problem:
So, I'm trying to figure out how to calculate the gravitational force of the earth. I am using Desmos to graph the equation so that will explain where $x$ and $y$ come from. Whenever I put in the information for Earth I got around 600 for the gravitational force I got 600 n/kg(which should be 9.8 n/kg).
Equation Details:
I'm using the following equation: $$y=0.000000000066743\frac{\left(\left(\frac{4}{3}\pi x^{3}\right)\cdot5520\right)62}{\left(x+0.8\right)^{2}}$$ Im basing everything on the following equation for gravity: $$F=G{\frac{m_1m_2}{r^2}}$$ The part that says $(43πx3)⋅5520$ is for calculating the mass of Earth based on x, which is the radius. The $(43πx3)$ part gets the volume in $m^{3}$ and then multiples it by $5520$, which is the number of kilograms 1 cubic meter of Earth is. I then put in 62 for $m_2$ since that is the average weight in kg of a human. I then did some research and figured out that G, the gravitational constant, is $0.000000000066743$. Now, to get $r^{2}$, I did $(x+0.8)^2$ since x is the radius, thus the distance from the center of the Earth to the crust, and then added 0.8 since that is half the average height of a human.
What Have I Tried:
I have tried checking if my density is correct by multiplying it by the volume of the Earth and it was correct. I can't find the gravitational constant from another source so that could be a possibly incorrect thing. I double-checked that my volume equation was correct and I also checked that I'm using the right units of measurement. Thanks for any help and feel free to ask questions about any equations/anything in general.