C2d3 has a solubility product constant of 9.14×10−9. what is the molar solubility of c2d3?

The correct answer for the question that is being presented above is this one:

We need to express the ksp expression of C2D3
C2D3
= (2x)2(3x)3
= 108x5 

Then set that equation equal to your solubility constant 

9.14x10-9 = 108x5 
x = 9.67x10-3 

So the molar solubility is 9.67x10-3

No a triangle cannot be formed because when you add the two smallest number together (which would be 11) the have to be bigger than the number it is "against" ( which would be 12)