Which instrument, shaped as an X, is used for enlargement and reduction of drawings?

• A. Caliper
• B. Ruler
• C. Proportional Divider
• D. Compass

Answer: (C)

Scaling drawings with a fixed ratio is handled by a tool whose two arms cross and form an X. This proportional divider is built to keep a constant proportion between the two lengths it spans, so you can transfer measurements from one scale to another accurately.

How it works: the two legs are joined at a pivot and can be set to a specific ratio. When you open the arms to a certain width, the distance on one leg corresponds to a scaled distance on the other leg. By positioning one tip on a reference point and the other tip on the corresponding point, you can enlarge or reduce the drawing while preserving proportional relationships. This makes it ideal for moving between scales, like 1:2, 1:5, or 1:10, without recalculating each measurement.

Why the other tools don’t fit: a caliper measures precise distances with jaws but isn’t used for scaling drawings; a ruler provides straight measurements or lines but doesn’t preserve a ratio between two lengths; a compass creates circles and arcs rather than translating linear dimensions between scales. The proportional divider’s ability to maintain a fixed ratio between two distances is what enables accurate enlargement or reduction, which is exactly what this item is designed to do.