An augmented fourth (tritone) has three major seconds. C—F♯.
189. A fifth is an interval comprising four seconds.
A diminished fifth has two minor and two major seconds. C—G♭.
A perfect fifth has one minor and three major seconds. C—G.
An augmented fifth has four major seconds. C—G♯.
190. A sixth is an interval comprising five seconds.
A minor sixth has two minor and three major seconds. C—A♭.
A major sixth has one minor and four major seconds. C—A.
An augmented sixth has five major seconds. C—A♯.
191. A seventh is an interval comprising six seconds.