Billy likes to go cycling.

Question

His bike has wheels of diameter 80 cm.

He has invented a counter for his bike, which counts the number of revolutions the wheels make.

One day the counter shows 210 revolutions.

How far has Billy cycled?

Give your answer to the nearest metre.

Answer 1

Each revolution is equal to one circumference of the wheel, so the distance Billy travels is:

distance = number of revolutions · circumference of wheel

distance = 210·2π·r

distance = 210·2π·(0.8) = ____?

Note that since the problem wants the answer in meters, I converted the 80 cm to 0.8 m. Round to the nearest meter.