Can you convert a decimal to a radical in simplest form?

Hello,

Can you help me find how to convert a decimal number to a radical (not rational) in simplest form? I need the answer with the check mark in it. ;^) For example, 3(check mark)5 = 6.70820394. But, how do you get that in reverse if you only know the decimal answer?

Otherwise, do you know of an online calculator or solver, or something like the TI-83 Graphing Calculator that would convert this?

Thanks,

Dan

PS

This seems to be essential for pre-calc, calc, and trig problems, but I haven't found an answer after several hours of searching on the Internet. Thanks for the help.

Re: Can you convert a decimal to a radical in simplest form?

I was searching for the same answer, and what's crazy about it is the answer I was looking for was from the same decimal you asked for, except mine was 6.708203932. Just thought that was neat. But, did you ever receive an answer about this? When I put in (-8-(-5))^2+(-4(2))^2 and put it under a square root bracket, I get 6.708203932. I need the answer to be a square root answer. The answer itself is 3 bracket(4) but I need the calculator to give me that answer instead of a decimal.