in music theory. These include the following: The root of some of these terms comes from Latin sesqui- "one and a half" (from semis "a half" and -que "and") describing the ratio 3:2. Notes Citations External links Superparticular numbers applied to construct pentatonic scales by David Canright. De Institutione Arithmetica, liber II by Anicius Manlius Severinus Boethius Rational numbers