When we analyze the relationships between different quantities, identify their units of measurement, and convert these quantities for equal comparison, we are using dimensional analysis. Dimensional analysis uses a ratio, or conversion factor, to change units of measurement while maintaining the value of the measurement. In a conversion factor, the numerator and denominator equal the same amount, just in different fractionsFor example, to convert 3 miles into feet, you would multiply 3 miles by a conversion factor created from the units of miles and feet. Because 1 mile equals 5,280 feet, two conversion factors can be created:1 mile /5,280 feet or 5,280 feet/1 mileMultiplying any number, such as 3 miles, by either of these units. does not change the number's over value. To determine which conversion factor we use, we place the unit we do not want in the bottom, while we put the unit we want to get rid of on the top