Question

What is the volume of a board that measures 1.8cm by 8.8cm by 30.5cm? I just do 1.8 x 8.8 x 30.5 to get the answer of 483.12, right? You always just x everything for volume?

Answer 1

That is correct, almost. First, you have units attached cm³. Secondly, your 1.8cm limits the answer to be no more than two significant digits.

Answer 2

yes, just multiply length x width x height. If your instructor is picky about significant figures, you have too many in your answer of 483.12. You are allowed two from 1.8, two from 8.8 and three from 30.5; therefore, you are allowed only two for the answer (the smallest number of s.f in any of the numbers for a multiplication).

Answer 3

Sorry, I don't get what you mean that I can only have two in my answer

Answer 4

Here is a web site about significant figures. The rule says that, when multiplying or dividing, you may have no more s.f. than any of the numbers you are multiplying (or dividing). Since you have two numbers with two s.f., then your answer may have no more than two s.f. Your answer of 483.12 (the digits are correct), has 5 s.f. Since you may have only 2 s.f., that would be the 4 and the 8 and that's all. So you would express the answer as 4.8 x 10^2 and add the unit of cm^3. All of this is assuming you copied all of the problem correctly. For example, if the 1.8 cm x 1.8 cm was really 1.80 and 1.80, that would change the number of s.f. in the answer.
http://members.aol.com/profchm/sig_fig.html