When planning a piece, be it 3-Dimensional or 2-Dimensional, artists may sketch out what they want, and the dimensions of that work. Then they would have to scale it larger for real life.
Another way artists use math, is when working with proportion. When drawing figures and faces, the Golden Ratio is often used for guide of how the face and figure is set up.
Geometry is frequently used in art, including observational drawing, measuring, and designs, among many others.
Perspective is a key part in art, making sure that the objects in the background are smaller than the foreground, and that things are placed to show depth and accuracy.
