A giraffe can run about 14 meters per second. Find it's speed in miles per hour. (1 mi = 5280 ft; 1 m = 3.28)

14 meters per second x 60 = 840 meters per minutes x 60 = 50,400 meters per hour

Now lets change that to feet. Since each meter is 3.28ft we will see how many feet we can get with our 50,400 meters by multiplying it by 3.28

50,400 x 3.28 = 151,200 feet

To change to miles lets do 151,200/5,280 = is about 28.64 miles per hour rounded to the nearest hundredth

Be aware that in reality, a giraffe could not sustain the speed of 28.64 mph for more than a few minutes.