Pierre's unicycle wheel has a diameter of 80 cm.
a) How far does the unicycle move if the
wheel turns once?
Give your answer in metres, correct
to 2 decimal places.
b) Pierre enters a 100 m unicycle race.
How many times must the wheel rotate
completely in order for Pierre to
travel 100 m?
Give your answer to the nearest
whole number.
80 cm

a) The distance covered during one rotation is 251.20 cm

b) The wheel must complete 40 rotations to covera distance of 100m

Step-by-step explanation:

It is to be understood that a circle when rotated covers a distance equalling its circumference in one rotation.

a)Given the diameter of the cycle’s wheel= 80 cm  

Radius of the wheel= 40cm (r= diameter/2)

Circumference of the wheel= 2*3.14*40= 251.20 cm

Distance covered by the wheel in one rotation is 251.2 cm

b)  Distance to be covered during competition= 100m

We know that 1 m equals 100 cm Hence, 100 m would equal 10,000 cm

This distance would be covered in successive revolutions of the wheel. Let the wheel make “n” revolutions

Hence distance covered during one revolution* no of revolution= total distance to be covered  

251.2n= 10,000

n =10,000/251.2= 38.81

When rounded to the nearest whole number, “n” equals 40

Hence no of revolutions by the wheel is 40