79958.42

rounded to 3 shouldnt it be like 8.00 or 80.0?

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- Jan 30th 2010, 12:54 PMNismo[SOLVED] Easy Sig fig question
79958.42

rounded to 3 shouldnt it be like 8.00 or 80.0? - Jan 30th 2010, 01:04 PMe^(i*pi)
No, after all think about how far 8 and 80 are from 79958.42

What you should do is convert to standard form: $\displaystyle 7.995842 \times 10^4$

You can then round off the first part to 3sf which is 8.00 but you must bring back the 10^4 to give $\displaystyle 8 \times 10^4 = 80000$ - Jan 30th 2010, 01:39 PMQuacky
79958.42

Remember that with significant figures, 0 counts in the context of a 10 or 100 and so forth, so for example, in 405, the 0 is significant, whereas in 0423, the 0 is not significant.

Therefore, when rounding this to three significant figures, the answer is 80000, as e^(i*pi) said. - Jan 30th 2010, 04:59 PMskeeter
$\displaystyle 80000$ has only one significant figure.

$\displaystyle 8.00 \times 10^4$ has three significant figures. - Jan 31st 2010, 05:36 PMNismo
thxs everyone for the help.