# Question #11c21

Dec 2, 2014

This is a conversion factor and can be answered in two simple steps.

$S t e p 1$: write out tools

$1 g a l l o n = 3.79 L i t e r s$
$1 L i t e r = 1000 m i l l i l i t e r s$

$S t e p 2$: cancel out units then plug in the number of gallons in for x

$x \cdot \left(3.79 \frac{L i t e r s}{1 g a l l o n}\right) \cdot \left(1000 \frac{m i l l i l i t e r s}{1 L i t e r}\right) =$

solving this equation will allow you to convert gallons to milliliters. Understanding how to cancel units is an important tool for the sciences.

The reason unit cancellation is so effective is because anything divided by itself is 1 such as:

$\frac{2}{2} = 1 , \frac{x}{x} = 1 , \frac{L i t e r}{L i t e r} = 1.$

Therefore when you "cancel out" units you're essentially making a unit to equal 1.