[Haskell-cafe] haskell question

[IBRAHIM MOSHAYA]

please can you help me with this function:

Significant Figures
I need to write a function to return a given number (1st argument) to a 
given number of significant figures
(2nd argument). The function should be called sigFig and have a type 
signature of the form:
sigFig :: (???) => a -> Int -> a
For instance:
*Main> sigFig 123.456 2
120.0
*Main> sigFig 123.456 4
123.5
*Main> sigFig 0.987 2
0.99
*Main> sigFig 0.432 2
0.43
The type variable a will need to be constrained, but you should aim for the 
most general implementation you
can (replacing ??? above with the appropriate constraint(s)). You may make 
free use of Prelude functions.
Referring to [Jon03] you may wish to consider the use of functions / 
operators including:
/, div, mod, ^, ^^, **, round, fromIntegral, realToFrac

thanks alot