Consider Leonardo da Vinci's Study of Human Proportions according to Vitruvius, included in this chapter of the text. Identify the century in which Leonardo worked, and discuss his use of proportion in this piece. 

What will be an ideal response?

Leonardo worked in the fifteenth century C.E. As the title of the work indicates, Leonardo was fascinated with the ideas of Vitruvius, a Roman architect, who related the perfected male form to the perfect geometry of the square and the circle. In this particular work by Leonardo, the man stands inside a square defined by his height and the span of his arms, and a circle centered at his navel.