Question

Perform the following calculation of measured numbers. Give the answer with the correct number of significant figures. (2.075)(0.585)/(8.42)(0.0045)

Answer 1

I checked against the original problem to clarify the operations being performed. (2.075)(0.585)/ ((8.42)(0.0045))

First multiply 2.075 * 0.585 (retain all sig figs and save the rounding for the end)

Divide the result by 8.42 (again, retaining sig figs)

Divide the result by 0.0045 (again, retaining all sig figs)

Finally, we determine how to round. Since we only have multiplication/division we go by the number with the least number of sig figs. In this case, 0.0045 has the least number of sig figs (2) so we round the final answer to 2 sig figs.

Answer 2

The answer is: (2.075)(0.585)/(8.42)(0.0045) = 0.31965842187

In order to figure out the correct number of significant figures in your answer, you should count the number of significant figures in each of the measured numbers. The numbers 2.075 and 0.585 have 3 significant figures each, meanwhile the numbers 8.42 and 0.0045 have 3 and 2 significant figures. The least number of significant figures in any of the measured numbers is going to be 2. So that means the answer should be rounded to 2 significant figures which equals like 0.32 I believe.