National Adult Literacy Database

In this video tutorial, the instructor explains the concept of ratio and proportion, describing it as simply comparing one thing to another. It can be written as a fraction or as two numerals separated by a colon.

For example, if the recipe for a salad dressing calls for vinegar and oil in a ratio of 2:5, the cook could use two tablespoons of vinegar and five tablespoons of oil. If the cook decided instead to use six tablespoons of vinegar, then he would have to use 15 tablespoons of oil to maintain the proportion of the ingredients called for in the recipe.

The instructor also shows how ratio and proportion can be applied to scaling a diagram, using as an example two triangles that are supposed to be proportional.