The London Eye
The 80 spokes of The London Eye are made from 4 miles of cable. What is the approximate circumference of the wheel?
Age
14 to 16
Challenge level
Problem
The 80 spokes of The London Eye (a giant wheel) are made from 4 miles of cable.
Roughly what is the circumference of the wheel in metres?
1 mile is approximately 1600 metres
If you liked this problem, here is an NRICH task that challenges you to use similar mathematical ideas.
Student Solutions
Answer: 500 metres
80 spokes = 4 miles
80 $\times$ radius = 4 miles
20 $\times$ radius = 1 mile
20 $\times$ radius $\approx$ 1600 metres
radius $\approx$ 80 metres
circumference $\approx$ 160$\pi$ metres
$\approx$ 500 metres