1. What is a Triad?
NCVPS AP Music Theory

2. Tertian Harmony
Tertian Harmony is creating tonal harmony by stacking 3rds on top of each other. The foundation of tertian harmony is the triad. The triad is a three-note chord consisting of a 5th that is divided.
This is a Triad based on the note “A”. The interval between “A” and “E” is a 5th and it is divided by the “C#” which is the third.

3. Four Qualities of Triads
There are Four Qualities of Triads (Augmented, Major, minor, and diminished).
Augmented Major minor diminished

4. Major Triad
A Major Triad has three parts. The Root, the 3rd and the 5th. To identify the quality of the triad, you must identify the interval between the Root and the 3rd, and the 3rd and the 5th. A Major Triad has a Major 3rd between the Root and the 3rd and a minor 3rd between the 3rd and the 5th.
In this triad, the “Bb” is the Root, the “D” is the 3rd, and the “F” is the 5th.

5. Major Triad
The interval between the Root and 3rd (“Bb” to “D”) is a Major 3rd and the interval between the 3rd and 5th (“D” to “F”) is a minor 3rd. This interval structure makes the quality of this triad, Major.

6. Minor Triad
A minor triad has three parts. The Root, the 3rd and the 5th. To identify the quality of the triad, you must identify the interval between the Root and the 3rd, and the 3rd and the 5th. A minor triad has a minor 3rd between the Root and the 3rd and a Major 3rd between the 3rd and the 5th.
In this triad, the “C” is the Root, the “Eb” is the 3rd, and the “G” is the 5th.

7. Minor Triad
The interval between the Root and 3rd (“C” to “Eb”) is a minor 3rd and the interval between the 3rd and 5th (“Eb” to “G”) is a Major 3rd. This interval structure makes the quality of this triad, minor.

8. Augmented Triad
An Augmented triad has three parts. The Root, the 3rd and the 5th. To identify the quality of the triad, you must identify the interval between the Root and the 3rd, and the 3rd and the 5th. An Augmented triad has a Major 3rd between the Root and the 3rd and a Major 3rd between the 3rd and the 5th.
In this triad, the “C” is the Root, the “E” is the 3rd, and the “G#” is the 5th.

9. Augmented Triad
The interval between the Root and 3rd (“C” to “E”) is a Major 3rd and the interval between the 3rd and 5th (“E” to “G#”) is a Major 3rd. This interval structure makes the quality of this triad, Augmented.

10. Diminished Triad
A diminished triad has three parts. The Root, the 3rd and the 5th. To identify the quality of the triad, you must identify the interval between the Root and the 3rd, and the 3rd and the 5th. A diminished triad has a minor 3rd between the Root and the 3rd and a minor 3rd between the 3rd and the 5th.
In this triad, the “G” is the Root, the “Bb” is the 3rd, and the “Db” is the 5th.

11. Diminished Triad
The interval between the Root and 3rd (“G” to “Bb”) is a minor 3rd and the interval between the 3rd and 5th (“Bb” to “Db”) is a minor 3rd. This interval structure makes the quality of this triad, diminished.

12. Let’s Practice!
What is the Quality of this chord?

13. The Answer What is the Quality of this chord?
The quality of this chord is Major. From Root to 3rd (“E” to “G#”) is a Major 3rd and from 3rd to 5th (“G#” to “B”) is a minor 3rd. With a Major 3rd on the bottom and minor 3rd on top, the quality is Major.

14. Let’s Practice!
What is the Quality of this chord?

15. The Answer What is the Quality of this chord?
The quality of this chord is minor. From the Root to the 3rd (“Bb” to “Db”) is a minor third and from 3rd to 5th (“Db” to “F”) is a Major 3rd. With a minor 3rd on the bottom and a Major 3rd on top, the quality is minor.

16. Let’s Practice!
What is the Quality of this chord?

17. The Answer What is the Quality of this chord?
The quality of this chord is Major. From the Root to the 3rd (“Eb” to “G”) is a Major 3rd and from the 3rd to the 5th (“G” to “Bb”) is a minor 3rd. With a minor third on the bottom and Major 3rd on top, the quality is Major.

18. Let’s Practice!
What is the Quality of this chord?

19. The Answer What is the Quality of this chord?
The quality of this chord is Augmented. From the Root to the 3rd (“Bb” to “D”) is a Major 3rd and from the 3rd to the 5th (“D” to “F#”) is a Major 3rd. With a Major 3rd on the bottom and a Major 3rd on top the quality is Augmented.

20. Let’s Practice!
What is the Quality of this chord?

21. Let’s Practice! What is the Quality of this chord?
The Quality of this chord is minor. From the Root to the 3rd (“D” to “F”) is a minor 3rd and from the 3rd to 5th (“F” to “A”) is a Major 3rd. With a minor 3rd on the bottom and a Major 3rd on top, the quality of this chord is minor.

22. Let’s Practice!
What is the Quality of this chord?

23. The Answer What is the Quality of this chord?
The quality of this chord is Major. From the Root to the 3rd (“F#” to “A#”) is a Major 3rd and from the 3rd to the 5th (“A#” to “C#” is a minor 3rd. With a Major 3rd on the bottom and a minor 3rd on top, the quality is Major.

24. Let’s Practice!
What is the Quality of this chord?

25. The Answer What is the Quality of this chord?
The quality of this chord is diminished. From the Root to the 3rd (“B” to “D”) is a minor 3rd and from 3rd to 5th (“D” to “F”) is a minor 3rd. With a minor 3rd on the bottom and minor 3rd on top, the quality is diminished.

26. Let’s Practice!
What is the Quality of this chord?

27. The Answer What is the Quality of this chord?
The quality of this chord is Major. From the Root to the 3rd (“E” to “G#”) is a Major 3rd and from the 3rd to the 5th (“G#” to “B”) is a minor 3rd. With a Major 3rd on the bottom and a minor 3rd on top, the quality is Major.

28. Four Qualities of Triads
There are Four Qualities of Triads (Augmented, Major, minor, and diminished).
Augmented Major minor diminished