The scale degrees in which we find each type of seventh chord are shown in the following table:

Chord	Major Scale	Natural Minor Scale	Harmonic Minor Scale	Melodic Minor Scale
Dominant 7th.	V	VII	V	IV, V
Major 7th.	I, IV	III, VI	VI
Minor 7th.	II, III, VI	I, IV, V	IV	II
Diminished 7th.			VII
Half Diminished 7th.	VII	II	II	VI, VII
Augmented Triad, Major Seventh			III	III
Minor Triad, Major Seventh			I	I

Knowing the type of sevenths found in each scale degree can be useful in identifying seventh chords.