A value expressed as a percent is described as which dimensionality?

A value expressed as a percent is described as which dimensionality?

• A. It has units of percent
• B. Unitless
• C. It has units of fraction
• D. It has units of ratio

Answer: (B)

Percent expresses a ratio of a part to a whole, scaled by 100. Because both the part and the whole have the same units, those units cancel when forming the ratio, and multiplying by 100 doesn’t add any units. That makes the value effectively dimensionless—like 25% equaling 0.25 or 1/4. While you can describe it as a ratio or a fraction, in dimensional analysis these forms are treated as unitless, so the correct description is unitless.

Percent expresses a ratio of a part to a whole, scaled by 100. Because both the part and the whole have the same units, those units cancel when forming the ratio, and multiplying by 100 doesn’t add any units. That makes the value effectively dimensionless—like 25% equaling 0.25 or 1/4. While you can describe it as a ratio or a fraction, in dimensional analysis these forms are treated as unitless, so the correct description is unitless.