Final answer:
The product of 0.040 m and 811 m, when rounded to the correct number of significant figures, is 32 m², as the least number of significant figures in the factors is two.
Step-by-step explanation:
To express the product of 0.040 m and 811 m using the correct number of significant digits, we must first perform the multiplication and then round the result to the least number of significant figures present in the factors. The rule for multiplication and division with significant figures states that the final answer should have the same number of significant figures as the measurement with the fewest significant figures.
Calculating the product:
0.040 m × 811 m = 32.44 m²
The number 0.040 m has two significant digits, while the number 811 m has three significant digits. Thus, we must round our answer to two significant figures.
The correctly rounded answer is 32 m².