- #1

Ian Mount

- 3

- 0

I have a question asking me to find the volume of a rectangular prism. The dimensions are as follows:

x = 20 ± 0.2 cm, y = 30 ± 0.2 cm, z = 70 ± 0.4 cm

I am asked to report the answer with the correct number of significant figures and include the error.

What I have so far:

V = xyz = 42000 ± 558.93 cm

^{3}

So I'm stuck on determining how many significant figures the answer should have and how to round the error.

I'm leaning towards 3 significant figures because 20 ± 0.2 is anything between 19.8 and 20.2, which have 3 significant figures. The same can be said for the other given dimensions. Therefore the volume would be V = 4.20*10

^{4}cm

^{3}.

Also, I'm not sure how to round errors. Do I round to the same number of significant figures or do I round to the same precision as the answer? If it's the same precision, assuming three significant figures, the answer would be 4.20*10

^{4}± 6*10

^{2}cm

^{3}. This feels correct, if you know what I mean.

Any help would be greatly appreciated. Thanks!