What is used to represent the quantity being measured in a table or a chart or in a formula or equation?

The quantity being measured in a table, chart, formula, or equation is typically represented by a variable or a label, often denoted by letters or symbols. For instance, in a mathematical equation, variables like (x) and (y) represent specific quantities, while in a table, column headings indicate the type of data being measured. Moreover, numerical values are used to quantify these variables, providing a clear representation of the data being analyzed.