Symmetry is achieved when parts of an object are arranged along an imaginary center line. Proportion is the relation of one part to another, or of parts to the whole, in respect to size, height, width and scale. Symmetry provides balance and aesthetic appeal.
Symmetry can be defined as the "evenness" of a structure, painting, or a face. the more symmetrical things are the more appealing they seem to the audience. As for proportion, it can be simplified to mean the size of something or the amount of space it takes compared to a certain area. Both of these things are important to an artist because depending an the balance of the two it can alter the experience of the viewer, hence making it either more, or less visually appealing.
