Dell Optiplex 9010 case fan pinout

So I recently bought an Dell Optiplex 9010 motherboard with i7-3770. I installed it in a different case, and the problem is that Dell pinout is 5 pin, and my fan has only 3 pin connector. When I'm gaming the temperatures are getting really high like 65-90C on CPU and GPU and the fans are really noisy. Does someone has a diagram how to plug it in? Like I think when I would grind the connector on the fan it should fit in perfectly. Thanks for all asnwers.