Bicycle Tire

A 26-inch (diameter) bicycle tire is being calibrated with a speedometer. Approximately how many revolutions of the wheel are equal to 1 mile?
Source: NCTM Math Teacher 2008

Circumference of tire
2\pi r=\pi d where d is the diameter.
Length of 1 revolution = 26\pi in.
Let x be the number of revolutions in 1 mile.
x\times 26\pi in\times\dfrac{1 ft}{12 in}\times\dfrac{1 mile}{5280 ft}=1 mile
x=\dfrac{12\times 5280}{26\pi}=775.7

Answer: 775.7 revolutions


About mvtrinh

Retired high school math teacher.
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