***10 points*** Chem help?

Common Ion

At some other temperature, a solid sample of Ca(OH)2 is shaken with 0.0100 M CaCl2.

Once equilibrated, some solid Ca(OH)2 remains undissolved.

The solution is filtered and a 15.00 mL sample requires 20.64 mL of 0.0100 M HCl to neutralize it.

Calculate the value for Ksp of Ca(OH)2 from this data.

I found Ksp = 3.20×10-6

What is the molarity of Ca(OH)2 which is dissolved in this solution?

I found 6.88×10-3 M

What is the solubility of Ca(OH)2 in this solution, in g/100mL?

g/100mL

I can't get part c... I'm so frustrated. If someone could show me how to find the solubility I would really appreciate it. Thank you in advance.