First we convert feet into meters, since 1 feet is 0.3048 m: 275 feet * 0.3048 = 83.82m.
Then we do: 83.82m / 3.23s = 25.9504644 m/s.
Then we convert that into miles per hour by 2.23694, so we do:
25.9504644 * 2.23694 = 58.0496318.
Then we round it to 58 mph.
So the answer is: The cheetah was running at 58 mph.
Hope this helped! c: