# Question #1188d

Jan 8, 2018

Some measurements are not compatible.

#### Explanation:

The simple answer is that it wouldn't make sense to mix different types of units. For example, take $c m$ and $m$. While they both take on the measurement of length, if I wanted to find the area of $c m$ by $m$ square, it wouldn't look right to mix the units to get $c m m$ therefore we convert both to one or the other. Sometimes conversions make the numbers a lot more nicer to work with as well.

Jan 9, 2018

An example of the case I mentioned above involves density. Density is mass/volume and is typically found in units of $\frac{k g}{m} ^ 3$. If you know the volume of an object in cubic centimeters, or cc, it would be wrong to multiply the density by volume with those units.
Assume your data is a density with units of $\frac{\text{kg}}{m} ^ 3$ and volume of an object in units of cc. First convert the volume units from cc to ${m}^{3}$. Then when you multiply the density by the volume, the ${m}^{3}$ units of the volume will cancel the ${m}^{3}$ in the denominator of the density, leaving you with kg.