Final answer:
The frequency of the note a perfect fifth below B4 is approximately 329.253 Hz.
Step-by-step explanation:
To find the frequency of the note a perfect fifth below B4, we need to calculate the frequency ratio of a perfect fifth, which is 3/2.
First, divide the frequency of B4 by 3/2:
B4 frequency / (3/2) = 493.88 Hz / (3/2) = 493.88 Hz * (2/3) = 329.253 Hz
Therefore, the frequency of the note a perfect fifth below B4 is approximately 329.253 Hz.