Question 1055525
Knowing the volume of the baking dish is not enough information.
You need to know the depth of the baking dish also or just the surface area of the baking dish. 
You can calculate the volume of frosting,
{{{V[avail]=pi*R^2*H=pi*(3/2)^2*4=9pi}}}{{{in^3}}}
Then the volume of frosting needed for the cake would be,
{{{V[needed]=A*(1/2)=A/2}}}
If you had the depth, D, of the baking dish (your units of volume should be cubic inches),
{{{A=256/D}}}
You could then compare volume needed and volume available.