Copyright © University of Cambridge. All rights reserved.
Cables can be made stronger by compacting them together in a hexagonal formation.
Here is a 'size 5' cable made up of 61 strands:
How many strands are needed for a size 10 cable?
How many for a size n cable?
Can you justify your answer?
Once you've had a go at the problem, click below to see how some 15 year old students worked on it.
Can you explain their reasoning?
Which of the four approaches makes the most sense to you?
What do you like about your favourite approach?
Can you think of any other approaches?