When solving any problem of this type it is helpful to use the following problem solving steps.
1) Write down what is known. *important*
Vi (initial velocity) = 0
t (time) = 3.2s
d = variable we are solving for
a (acceleration) = 9.8 m/s2
2) Which equation applies?
The correct formula will contain the known variables and only one unknown, which will be the variable we are solving for (d).
The correct formula is d = vi*t+1/2 at2 because vi=0, which makes the v0*t term drop out, leaving us with d=1/2at2
3) Now for the easy part, plug in and solve.
d = 1/2*9.8*3.22
The answer is 50.2m