To solve proportions, one must know how to work with fractions, set up ratios, cross multiply, and solve one-step algebraic equations. The document provides examples of using proportions to calculate the amount of sugar needed for cookies based on a recipe, the rate of snowfall per hour during a storm, and the exchange of US dollars to Argentine pesos at a given rate. Proportions can be seen in many real-world applications such as baking, weather, currency exchange, and other everyday situations.