12 Tone Equal Temperament (12TET)

Definitions:
Interval: The relationship between one note and another expressed in distance, or frequency.
Octave: An interval of a lower and higher version of the same note. Example: A4(440hz) and A5(880hz).

Question:
Multiply A4(440hz) twelve times by what number to arrive at its Octave A5(880hz)?

Answer:
The 12th Root of 2 = ¹²√2 = 2^1/12 = 1.0594630943592953...

Interesting Links:
•Equal Temperament Explained Georgia State
•Wikipedia