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AP Music Theory Practice Quiz: The iii (III) Chord

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 7 questions to check your progress.

Question 1 of 7

According to the provided text, which triad is generally used infrequently in the harmonic progressions of 18th-century style?

All Questions (7)

According to the provided text, which triad is generally used infrequently in the harmonic progressions of 18th-century style?

A) The tonic triad

B) The dominant triad

C) The mediant triad

D) The subdominant triad

Correct Answer: C

The text explicitly states, 'The mediant triad is rarely used in harmonic progressions of 18th-century style.'

In 18th-century music, which of the following chords would be encountered more frequently?

A) The mediant triad in a major key (iii)

B) The mediant triad in a minor key (III)

C) Both were used with equal frequency

D) Neither was used in this period

Correct Answer: B

The text states that the mediant triad is rarely used, but specifies that 'The mediant triad in a minor key—III—appears more often'.

What is the primary harmonic function of the III chord in a minor key, as described in the text?

A) To prepare the dominant

B) To function as a pre-dominant chord

C) To represent the relative major key

D) To act as a substitute for the tonic

Correct Answer: C

The content specifies that the III chord in a minor key 'appears more often in its role as representing the relative major key.'

When analyzing a notated score in G minor from the 18th century, the appearance of a B-flat major chord would most likely be identified as which of the following?

A) A i chord, functioning as the tonic

B) A V chord, functioning as the dominant

C) A III chord, representing the relative major

D) An unusual chord not typical of the style

Correct Answer: C

In G minor, the mediant is B-flat. A B-flat major triad is the III chord. The text states the function of the III chord in a minor key is to represent the relative major, which in the case of G minor is B-flat major.

Based on the provided information, what is the key difference in the usage of the mediant triad between major and minor keys in 18th-century style?

A) The mediant is common in major keys but rare in minor keys.

B) The mediant in minor keys (III) has a specific function related to the relative major, making it more common than the mediant in major keys (iii).

C) The mediant in major keys (iii) is always inverted, while the mediant in minor keys (III) is always in root position.

D) There is no difference in usage; both are equally rare.

Correct Answer: B

The text describes the mediant triad generally as 'rarely used' but then highlights that the III chord in minor keys 'appears more often' specifically because of its role 'as representing the relative major key,' implying a functional distinction and difference in frequency.

A student listening to a piece in A minor from the 18th century hears a progression that strongly suggests a temporary shift to the key of C major. Which triad is most likely being used to create this effect?

A) The i chord (A minor)

B) The III chord (C major)

C) The V chord (E major)

D) The vi chord (F major)

Correct Answer: B

The relative major of A minor is C major. The text states that the III chord in a minor key serves the role of 'representing the relative major key.' Therefore, a C major triad (the III chord) would be used to suggest the key of C major.

Which statement best summarizes the overall usage of the mediant triad in 18th-century harmonic practice, according to the text?

A) It is a foundational chord used in most progressions.

B) It is generally uncommon, but its appearance in minor keys is more frequent and functionally significant.

C) It is used exclusively in minor keys and never in major keys.

D) It is more important and more frequently used than the dominant triad.

Correct Answer: B

This statement accurately synthesizes both points from the text: the mediant triad is 'rarely used' in general, but the III chord in minor 'appears more often' due to its specific function.