* Get the code out of the main() method. With a simple program like this it may not matter as much, but it is a good habit to get in. Read why MainIsAPain (that's a link).
* Don't use floats unless you have too (which is rare). Use doubles for better precision.
* The indentation is almost right, but you should format your code as you write.
* Minor: you can use System.out.print() to print a prompt without going to the next line.
All things are lawful, but not all things are profitable.