How do I solve for Ksp The problem gives that the solubility of Silver dichromate is $8.3\times10^{-3} g/100mL$. I need to find $K_{sp}$ which is supposed to be $2.8\times10^{-11}$. 

$K_{sp}$ is $\ce{[Ag+]^2[Cr2O7^{2-}]}$

I changed the $8.3\times 10^{-3}$ from g/mL to mol/L and got $1.9\times 10^{-8}$.

Silver dichromate breaks into 2 Ag and one dichromate. 

So that would be $(2 \times 1.9\times10^{-8})^2 \times ( 1.9\times10^{-8})$ 

That's what I did but it's not giving me the right answer. Where am I going wrong here?
The problem gives that the solubility of Silver dichromate is $\mathrm{8.3\cdot10^{-3} g/100\,mL}$.
[…]
I changed the $8.3\cdot10^{-3}$ from g/mL to mol/L and got $1.9\cdot10^{-8}$.
[…] Were am I going wrong here?

Was the solubility given in $\mathrm{g/100\,mL}$?
$$\mathrm{8.3\cdot10^{-3} g/100\,mL = 8.3\cdot10^{-2}\,g/L = \frac{8.3}{431.72}\,mol/L = 1.92\cdot10^{-4}\,mol/L}$$