Full Idea
The major Forms of the beautiful are order, symmetry and delimitation, and these are very much objects of the proofs of the mathematical sciences.
Gist of Idea
Beauty involves the Forms of order, symmetry and limit, which can be handled mathematically
Source
Aristotle (Metaphysics [c.324 BCE], 1078a31)
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.400