Question

A bicycle has a diameter 75cm.
a) calculate the length of its circumference to one decimal place.
b) How many times will the wheel rotate if a girl rides the bicycle for 1km?
Give your answer to the nearest whole number.

Answer 1

a)  235.7cm (c=πd)
b) 424 rotations (rotations= distance/circumference)

Answer 2

Diameter = 75 Cm ∴Radius = 75/2Cm
Circumference of circle = 2πr
=2×22/7×75/2
 = 235.5Cm

Rotation In 235.5 Cm = 1 
Rotations in 1 km = 100000/235.5   {1km = 100000Cm}
= 424 Rotations