Extremes and means of a proportion

Aviation Mechanic General (AMG) practice question 4 of 25 on Mathematics. ACS element AM.I.H.K5 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONIn any proportion, the product of the extremes is equal to

Athe product of the means
Bthe sum of the means
Cthe quotient of the means

Show the answer and explanation

Correct answer: A. the product of the means

A — correct The handbook states that in any proportion the product of the extremes equals the product of the means, as in 2:3 = 4:6 where 2 × 6 = 3 × 4 = 12.
B — incorrect The means are multiplied, not added; in 2:3 = 4:6 the sum 3 + 4 = 7 does not equal 2 × 6 = 12.
C — incorrect The relationship is a product, not a division; 3 ÷ 4 does not equal 2 × 6.

BACKGROUND

A proportion is a statement of equality between two or more ratios, such as 3:4 = 6:8, read as 3 is to 4 as 6 is to 8. The first and last terms (3 and 8) are called the extremes, and the second and third terms (4 and 6) are called the means. In any proportion, the product of the extremes equals the product of the means: 3 × 8 = 24 and 4 × 6 = 24. This rule is the basis for solving a proportion when three terms are known and one is unknown.

STUDY TIP

Picture the proportion written across one line; the outer numbers are the extremes and the inner numbers are the means.

KEY POINTS

Proportion: two equal ratios, e.g. 3:4 = 6:8.
Extremes are the first and last terms; means are the middle terms.
Product of extremes = product of means.

SOURCES

FAA-H-8083-30B ch03 "Extremes and Means"

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