FAA Aviation Mechanic General (AMG)Aircraft Drawings, Weight and BalanceMedium
A technician is examining a detail drawing of a sheet metal bracket labeled 'SCALE: 1:2.' Using a scale ruler, a feature measures 3.00 inches on the drawing. What is the actual length of that feature on the finished part?
- A3.00 inches
- B6.00 inches
- C9.00 inches
- D1.50 inches
Show answer & explanationAnswer & explanation
Correct answer: B. 6.00 inches
A scale of 1:2 means the drawing is drawn at half the actual size, so every measured drawing dimension represents twice that value on the real part. 3.00 in (drawing) × 2 = 6.00 in actual.
Why the other options are wrong
- A. This assumes the drawing is full scale, ignoring the 1:2 ratio.
- C. This does not correspond to any correct application of the 1:2 scale.
- D. This results from dividing instead of multiplying by the scale factor.
Drawing Scale
A ratio comparing the size of a feature on a drawing to its actual size on the part; 1:2 means the drawing is half the actual size.
- 1:1 is full scale (drawing = actual size)
- 1:2 means drawing is half size, so actual = drawing measurement × 2
- 2:1 means drawing is enlarged (twice actual size)
Memory trick: First number is the drawing, second is the real part — 1:2 means drawing is small, part is big.