Sept 9 (Reuters) - Affirm Holdings Inc reported a 71% rise in quarterly revenue on Thursday, driven by a rise in the number of merchants and active consumers on its buy-now-pay-later platform. Total revenue rose to $261.8 million during the fourth quarter ended June 30, from $153.3 million, a year earlier. (Reporting by Sohini Podder and Akanksha Rana in Bengaluru; Editing by Shailesh Kuber)