Dave C. answered 01/16/17
Master the guitar - Improve your songwriting
In the equal temperament system, every pitch is the same distance apart from both adjacent chromatic pitches. The next note you would need to find above C4 (262 Hz) is C#4. This is calculated using the 12th root of 2 (12√2 ≈ 1.05946). Multiply 262 * 1.05946 to get 278 Hz (rounded). To find D4, you could multiply 278 * 1.05946. You could easily find the rest by using this method, but due to rounding, this wouldn't be a very precise way to do it. Better to use an absolute formula: To find the frequency, Pn, of a note in 12-TET, the following definition may be used: Pn = Pa(12√2)(n − a)
Good luck with those 12th roots!