Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. An industrial chemist studying this reaction fills a flask with of sulfur dioxide gas and of oxygen gas, and when the mixture has come to equilibrium measures the partial pressure of sulfur trioxide gas to be . Calculate the pressure equilibrium constant for the reaction of sulfur dioxide and oxygen at the final temperature of the mixture. Round your answer to significant digits.