The answer must contain
the same number of significant figures as were present in the measurement with
the fewest number of significant figures.

Question:
A student measures the length of a table to be 120.2 cm and the
width to be 29.5 cm. What is the area of the table. Express the
answer with the proper number of significant figures.

Answer:

Step 1:To obtain the area
of the table, we perform the following multiplication using the calculator.

29.5 cm x 120.2 cm = ?

The calculator displays the answer to be 3545.9.
The unit is in cm^{2}.

Step
2: Inspect each number and determine the number of significant figures
in each number.

29.5

3 significant figures (This measurement has the fewest number of significant
figures.)

120.2

4 significant figures

The measurement 29.5 limits the number
of significant figures in the answer to 3 significant figures.

The answer is 3.55 x 10^{3 }cm^{2};3 significant figures.

Going back to the example in section
1.7, the answer is

3.85 x 10^{3} cm^{2}.

The answer has 3 significant figures because the length
measurement is the measurement with the fewest significant figures (i.e. 3 significant
figures). It limits the final answer to 3 significant figures.