Which feature would help you quickly determine if a ruler is marked in standard (imperial) units or metric units?

• A. The ruler has numbers printed in red ink.
• B. The ruler is divided into centimeters and millimeters.
• C. The ruler is divided into inches and fractions of an inch.
• D. The ruler is made of metal.

Answer: (C)

Verified step by step guidance

1. Understand that standard (imperial) units and metric units use different base units for length measurement: inches for imperial and centimeters/millimeters for metric.
2. Identify the markings on the ruler: if the ruler is divided into centimeters and millimeters, it is using metric units.
3. If the ruler is divided into inches and fractions of an inch (such as halves, quarters, eighths), it is using standard (imperial) units.
4. Note that features like the color of the numbers or the material of the ruler (metal or not) do not determine the measurement system.
5. Therefore, the key feature to quickly determine the unit system is to look at the type of divisions on the ruler—whether they are metric (cm and mm) or imperial (inches and fractions).