To find the number of bacteria in a sample that weighs 9 grams, we can use a simple multiplication based on the initial measurement of 3.4 x 10^5 bacteria per gram.
- First, we multiply the number of bacteria in 1 gram by the weight of the new sample (9 grams):
\[ 3.4 \times 10^5 \text{ bacteria/gram} \times 9 \text{ grams} = 30.6 \times 10^5 \text{ bacteria} \]
- Next, we convert \(30.6 \times 10^5\) into scientific notation. To do this, we need to adjust it so that there's only one non-zero digit to the left of the decimal:
\[ 30.6 \times 10^5 = 3.06 \times 10^6 \]
Hence, the number of bacteria in a 9 gram sample is:
\[ \boxed{3.06 \times 10^6} \]