Luca Pacioli
Pacioli, Luca
Born circa 1445; died after 1509. Italian mathematician; mathematics teacher.
In 1494, Pacioli published Summa de arithmetica, geometria, proportions et proportionalita, a work dealing with arithmetic operations and with algebraic equations and the application of such equations to geometry. Under the influence of his friend Leonardo da Vinci, he spent the years from 1496 to 1499 writing De divina proportione (published 1509). This treatise contains a theory of geometric proportions, notably the rules for the golden section—the division of a line in extreme and mean ratio.