user: ### NOW ANSWER:
Question: Which Ratio has a Similar ISO A size of A3?
Columns: ['Name', 'in × in', 'mm × mm', 'Ratio', 'Similar ISO A size']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['ANSI A', '8.5 × 11', '216 × 279', 1.2941, 'A4']
SQL:

assistant: SELECT AVG("Ratio") FROM "Table" WHERE "Similar ISO A size" = 'A3';