Answer: frequency = 523.2 Hz
Step-by-step explanation:
One octave higher = 2f of the last octave.
For instance, if C2 = 4 Hz
A octave higher will be C3 in which its frequency will be 2 × 4Hz = 8Hz
Back to the question.
One octave higher frequency will therefore equal to:
2f = 2 × 261.6 = 523.2 Hz