Coefficient/ˌkəʊɪˈfɪʃnt/ Definition 1 of 3Pro Tip 1/3Quantity Indicator Coefficients show how many times to use the variable in an algebraic expression. If 3y = 12, coefficient 3 indicates y is used three times to get 12. Pro Tip 2/3Not Always Numbers Coefficients can be numbers or parameters like pi, especially in formulas or equations. In the equation C = 2πr, π is the coefficient of r. Pro Tip 3/3Scale Factor In geometry, coefficients scale a figure's dimensions without changing its shape. A scale coefficient of 2 enlarges a shape’s dimensions by 2 times.