A proportion is a statement that shows two ratios are equal. In proportions you can use cross products (butterfly method) to find out if they are equal. you could use it to determine miles per hour, and the unit price of something. A ratio is more like two numbers of the same kind as is written as one fraction instead of like two fraction as a proportion is. example suppose you had a bowl of jellybeans. you have 2 black and 4 read in a bowl your ratio would be 2/4 then you reduce that fraction to be 1/2.