This website talks about geometry in perspective. In old, famous paintings you can clearly see how the artist used geometry in his/her work.
This art piece by Paulo Uccello called ‘Perspective Drawing of a Chalice’, shows how even back then, geometry was used in paintings. Artists always value how geometry can help their art become realistic, and visually pleasing.
http://www.artyfactory.com/perspective_drawing/perspective_11.html