Which of the following are true about a conversion factor? Select all that apply. It is an expression of dosage strength divided by the ordered dose. The numerator is equal to the denominator. A conversion factor is used to cancel unnecessary units of measurement, leaving the desired unit. Honversion factors are expressed using only the metric units of measurements.

Let's analyze each statement about conversion factors to determine which are true: 1. **It is an expression of dosage strength divided by the ordered dose.** - This statement is **not true**. A conversion factor is typically a ratio that relates two different units of measurement, not specifically about dosage strength and ordered dose. 2. **The numerator is equal to the denominator.** - This statement is **not true** in the context of conversion factors. While a conversion factor can be expressed as a fraction where the numerator and denominator are equal (which equals 1), this is not a requirement for all conversion factors. 3. **A conversion factor is used to cancel unnecessary units of measurement, leaving the desired unit.** - This statement is **true**. The primary purpose of a conversion factor is to convert one unit of measurement to another, effectively canceling out the units that are not needed. 4. **Conversion factors are expressed using only the metric units of measurements.** - This statement is **not true**. Conversion factors can be used with any system of measurement, including metric, imperial, and others. Based on this analysis, the only true statement is: - A conversion factor is used to cancel unnecessary units of measurement, leaving the desired unit.