[plt-scheme] Specifying number precision to display

Hi all,

I'm looking for something like the C-style printf format strings that 
let you specify how many digits of a decimal to display--and also to 
force my output to display as a decimal, not a fraction.

It seems to me this has got to be easily accessible somewhere...the 
closest I've found is the pretty.ss parameter 
pretty-print-exact-as-decimal, and that apparently only affects use of 
the pretty-print procedure.

Any tips?

Thanks,
jmj

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Jordan Johnson (Email manipulator #22483617)