A ratio is a mathematical expression that compares two or more quantities, showing the relative size of one quantity to another. It is often written in the form of a fraction, such as 3/4, or with a colon, like 3:4. Ratios help to simplify complex relationships and make it easier to understand proportions in various contexts, such as in cooking, finance, or statistics. Ratios can be used to analyze data and make decisions. For example, in finance, a company might use the debt-to-equity ratio to assess its financial health by comparing its total debt to its shareholders' equity. This allows stakeholders to evaluate the risk and stability of the business.