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ASVAB · Geometry

What is the circumference of a circle with diameter 14? (Use π ≈ 22/7)

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

44

  1. A 154
  2. B 88
  3. C 44
  4. D 22

Why this is the answer

Circumference = πd = (22/7) × 14 = (22 × 14)/7 = 22 × 2 = 44 units. Or use 2πr with radius = 7: C = 2π(7) = 14π = 14 × (22/7) = 44. Circle formulas: (1) Diameter = 2 × radius, so radius = diameter/2; (2) Circumference C = πd = 2πr (length around the circle); (3) Area = πr² (surface inside); (4) The number π ≈ 3.14159 ≈ 22/7 (rough approximation). The 22/7 approximation works exactly when the radius or diameter is a multiple of 7. The ASVAB sometimes uses 22/7 to enable clean arithmetic without a calculator. For circles where π must remain symbolic, express answers in terms of π: a circle with radius 5 has C = 10π and A = 25π. The relationship C = πd is the geometric definition of π: π is the ratio of any circle's circumference to its diameter — always constant regardless of circle size.
Source: ASVAB Math Knowledge — Circle Circumference

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About this topic: Geometry

Geometry on the Mathematics Knowledge section covers angles, triangles (including the Pythagorean theorem), circles, polygons, perimeter, area and volume, and basic coordinate geometry such as slope. Formulas are not provided, so they must be memorised. This is one of 19 Mathematics Knowledge questions on geometry, each with a full explanation on a single study page.

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