Or in case you'd like to know how to actually calculate this scenario, assuming we know both players' hands and the flop as shown and you want the running nines to make your quads:
2/45*1/44 = 0.1010101010101...%, which is about 1000 to 1.
Originally Posted by slipknot4life
1080 to 1, Super System
This is close but doesn't account for knowing your opponents hole cards like in our scenario. It only assumes you know your hole cards and the flop and that you want to know the odds of hitting two specific running cards in the deck.
2/47*1/46 = 0.0925% which is about 1080 to 1.