Help with this simple physics problem?

I have a physics problem in my pre-algebra book and wanted to know if I got the correct answer. "The time T in seconds that it takes an object to fall D feet can be estimated by using D = 0.5gt^2. In this formula, G is acceleration due to gravity, 32ft/s^2. If a ball is dropped from the top of a 55-foot... show more I have a physics problem in my pre-algebra book and wanted to know if I got the correct answer.

"The time T in seconds that it takes an object to fall D feet can be estimated by using D = 0.5gt^2. In this formula, G is acceleration due to gravity, 32ft/s^2. If a ball is dropped from the top of a 55-foot building, how long does it take to hit the ground?

I came up with 0.33 seconds. Is this right?
Update: I found the problem I ran into is that I was squaring 32ft/s.

In the book, it gives acceleration due to gravity as 32ft/s^2.

Why does it read as "seconds squared"? What do I do with that squared part? It seems like I'm supposed to ignore it.