SkyDrill

Rounding a bearing diameter to the nearest hundredth

Aviation Mechanic General (AMG) practice question 25 of 25 on Mathematics. ACS element AM.I.H.R3 · difficulty: standard. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONThe outside diameter of a bearing measures 3.1648 centimeters. Rounded to the nearest hundredth, the diameter is

  1. A3.17 centimeters
  2. B3.165 centimeters
  3. C3.16 centimeters
Show the answer and explanation

Correct answer: C. 3.16 centimeters

  • A — incorrect Rounding up would require the digit after the 6 to be 5 or greater; it is 4.
  • B — incorrect 3.165 is rounded to the nearest thousandth, not the nearest hundredth.
  • C — correct The hundredths digit is 6 and the digit to its right is 4; since 4 is less than 5, the 6 is left unchanged, giving 3.16.

BACKGROUND

Rounding off keeps the digits for a certain number of places and discards the rest. When the digit immediately to the right of the last retained digit is 5 or greater, round up by 1; when it is less than 5, leave the last retained digit unchanged. For 3.1648 centimeters rounded to the nearest hundredth, the hundredths digit is 6 and the digit to its right is 4, so the 6 stays and the result is 3.16. By contrast, 2.1938 rounded to the nearest tenth becomes 2.2 because the 9 after the 1 causes a round-up.

STUDY TIP

First locate the place you are rounding to, then decide based only on the next digit to the right.

KEY POINTS

  • Nearest hundredth keeps two decimal places.
  • 3.1648: next digit 4 is less than 5, so 3.16.
  • Digits of 5 or more would round the retained digit up.

SOURCES

  • FAA-H-8083-30B ch03 "Rounding Off Decimal Numbers" (bearing diameter example)
Practice the Aviation Mechanic General (AMG) test →Timed 60-question exam, by ACS area, or review your misses. Free.
MORE ON MATHEMATICS

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.