# Sig figs

just to clarify on sig figs...for example if a question asked what is the volume of a box that is 85 m by 92 m by 95 m, the answer is 742900 m^3 but since each number has 2 sig figs, the answer must be reported as 740,000 m^3?

is that correct?

also, 150 has 2 sig figs but 150. has 3...right?

thanks.

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NateTG
Homework Helper
dnt said:
just to clarify on sig figs...for example if a question asked what is the volume of a box that is 85 m by 92 m by 95 m, the answer is 742900 m^3 but since each number has 2 sig figs, the answer must be reported as 740,000 m^3?

is that correct?

also, 150 has 2 sig figs but 150. has 3...right?

thanks.
You've got it.
Actually, it's probably better form to write it as:
$$7.4 \times 10^{5}$$
Since that will leave no doubt about whether the zeros are significant.

thanks.

regarding the "150 vs 150." - i know how many sig figs it has but can someone explain WHY the decimal at the end makes the 0 significant in 150. compared to only 150?

DB
whozum said:
umm..i dont think so, i think 150.0 has four sig figs, 150. has three, and 150 two.

dnt, the decimal in 150. is just a way of saying that, to the limits of your measuring tool, for example: this stick is exactly 150. metres , not 149, not 151, but 150.
and in the case of 150.0, it would be implied that your measuring tool can measure to the tenth of a metre and for example you could say: this stick measures exactly 150.0 meters, not 150.1 not 150.2, but 150.0, though you know nothing about the second decimal place. it could be 150.01, 150.0[1-9], u dont know, its too precise for ur measuring tool. u get it?

HallsofIvy
Homework Helper
It would, of course, be better to write them as 1.5 x 102 if you intend 2 sig figures, 1.50x102 if you intend 3, 1.500x102 if you intend 4.

DB said:
umm..i dont think so, i think 150.0 has four sig figs, 150. has three, and 150 two.
i didnt say it IS 150.0, it is understood as 150 and nothing else. exactly 150, it has 3 significant figures.

DB
sorry, i missunderstood ur statement