To convert the number \( 7.3 \times 10^{-8} \) into decimal notation, you need to move the decimal point 8 places to the left since it is a negative exponent.
Starting with 7.3:
- Move the decimal point 1 place to the left to get 0.73.
- Move it another 1 place to get 0.073.
- Move it another 1 place to get 0.0073.
- Move it another 1 place to get 0.00073.
- Move it another 1 place to get 0.000073.
- Move it another 1 place to get 0.0000073.
- Move it another 1 place to get 0.00000073.
- Move it another 1 place to get 0.000000073.
So the answer is:
0.000000073