Name | Formula | Solution | Mean of octave (2/1) |

Arithmetic | a − b = b − c | b = (a + c)/2 | B = 3/2 (perfect fifth) |

Geometric | a/b = b/c | b = $\sqrt{\text{ac}}$ | b = $\sqrt{2}$ (tritone) |

Harmonic | (a − b)/a = (b − c)/c | b = 2ac/(a + c) | b = 4/3 (perfect fourth) |