Watch this video from Virtual Nerds to learn about a proportion and how it is formed.
http://www.virtualnerd.com/pre-algebra/ratios-proportions/proportionality/determine-proportionality/proportion-definition
Source: Virtual Nerds
Follow this link to watch a video explaining how to write a proportion from a word problem.
http://www.virtualnerd.com/pre-algebra/ratios-proportions/proportionality/solving-proportions/proportion-word-problem-set-up
